powerpc: Merge enough to start building in arch/powerpc.

This creates the directory structure under arch/powerpc and a bunch
of Kconfig files.  It does a first-cut merge of arch/powerpc/mm,
arch/powerpc/lib and arch/powerpc/platforms/powermac.  This is enough
to build a 32-bit powermac kernel with ARCH=powerpc.

For now we are getting some unmerged files from arch/ppc/kernel and
arch/ppc/syslib, or arch/ppc64/kernel.  This makes some minor changes
to files in those directories and files outside arch/powerpc.

The boot directory is still not merged.  That's going to be interesting.

Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/vmlinux.lds.S

@@ -0,0 +1,172 @@
+#include <asm-generic/vmlinux.lds.h>
+
+OUTPUT_ARCH(powerpc:common)
+jiffies = jiffies_64 + 4;
+SECTIONS
+{
+  /* Read-only sections, merged into text segment: */
+  . = + SIZEOF_HEADERS;
+  .interp : { *(.interp) }
+  .hash          : { *(.hash)		}
+  .dynsym        : { *(.dynsym)		}
+  .dynstr        : { *(.dynstr)		}
+  .rel.text      : { *(.rel.text)		}
+  .rela.text     : { *(.rela.text) 	}
+  .rel.data      : { *(.rel.data)		}
+  .rela.data     : { *(.rela.data) 	}
+  .rel.rodata    : { *(.rel.rodata) 	}
+  .rela.rodata   : { *(.rela.rodata) 	}
+  .rel.got       : { *(.rel.got)		}
+  .rela.got      : { *(.rela.got)		}
+  .rel.ctors     : { *(.rel.ctors)	}
+  .rela.ctors    : { *(.rela.ctors)	}
+  .rel.dtors     : { *(.rel.dtors)	}
+  .rela.dtors    : { *(.rela.dtors)	}
+  .rel.bss       : { *(.rel.bss)		}
+  .rela.bss      : { *(.rela.bss)		}
+  .rel.plt       : { *(.rel.plt)		}
+  .rela.plt      : { *(.rela.plt)		}
+/*  .init          : { *(.init)	} =0*/
+  .plt : { *(.plt) }
+  .text      :
+  {
+    *(.text)
+    SCHED_TEXT
+    LOCK_TEXT
+    *(.fixup)
+    *(.got1)
+    __got2_start = .;
+    *(.got2)
+    __got2_end = .;
+  }
+  _etext = .;
+  PROVIDE (etext = .);
+
+  RODATA
+  .fini      : { *(.fini)    } =0
+  .ctors     : { *(.ctors)   }
+  .dtors     : { *(.dtors)   }
+
+  .fixup   : { *(.fixup) }
+
+	__ex_table : {
+		__start___ex_table = .;
+		*(__ex_table)
+		__stop___ex_table = .;
+	}
+
+	__bug_table : {
+		__start___bug_table = .;
+		*(__bug_table)
+		__stop___bug_table = .;
+	}
+
+  /* Read-write section, merged into data segment: */
+  . = ALIGN(4096);
+  .data    :
+  {
+    *(.data)
+    *(.data1)
+    *(.sdata)
+    *(.sdata2)
+    *(.got.plt) *(.got)
+    *(.dynamic)
+    CONSTRUCTORS
+  }
+
+  . = ALIGN(4096);
+  __nosave_begin = .;
+  .data_nosave : { *(.data.nosave) }
+  . = ALIGN(4096);
+  __nosave_end = .;
+
+  . = ALIGN(32);
+  .data.cacheline_aligned : { *(.data.cacheline_aligned) }
+
+  _edata  =  .;
+  PROVIDE (edata = .);
+
+  . = ALIGN(8192);
+  .data.init_task : { *(.data.init_task) }
+
+  . = ALIGN(4096);
+  __init_begin = .;
+  .init.text : {
+	_sinittext = .;
+	*(.init.text)
+	_einittext = .;
+  }
+  /* .exit.text is discarded at runtime, not link time,
+     to deal with references from __bug_table */
+  .exit.text : { *(.exit.text) }
+  .init.data : {
+    *(.init.data);
+    __vtop_table_begin = .;
+    *(.vtop_fixup);
+    __vtop_table_end = .;
+    __ptov_table_begin = .;
+    *(.ptov_fixup);
+    __ptov_table_end = .;
+  }
+  . = ALIGN(16);
+  __setup_start = .;
+  .init.setup : { *(.init.setup) }
+  __setup_end = .;
+  __initcall_start = .;
+  .initcall.init : {
+	*(.initcall1.init)
+	*(.initcall2.init)
+	*(.initcall3.init)
+	*(.initcall4.init)
+	*(.initcall5.init)
+	*(.initcall6.init)
+	*(.initcall7.init)
+  }
+  __initcall_end = .;
+
+  __con_initcall_start = .;
+  .con_initcall.init : { *(.con_initcall.init) }
+  __con_initcall_end = .;
+
+  SECURITY_INIT
+
+  __start___ftr_fixup = .;
+  __ftr_fixup : { *(__ftr_fixup) }
+  __stop___ftr_fixup = .;
+
+  . = ALIGN(32);
+  __per_cpu_start = .;
+  .data.percpu  : { *(.data.percpu) }
+  __per_cpu_end = .;
+
+  . = ALIGN(4096);
+  __initramfs_start = .;
+  .init.ramfs : { *(.init.ramfs) }
+  __initramfs_end = .;
+
+  . = ALIGN(4096);
+  __init_end = .;
+
+  . = ALIGN(4096);
+  _sextratext = .;
+  _eextratext = .;
+
+  __bss_start = .;
+  .bss       :
+  {
+   *(.sbss) *(.scommon)
+   *(.dynbss)
+   *(.bss)
+   *(COMMON)
+  }
+  __bss_stop = .;
+
+  _end = . ;
+  PROVIDE (end = .);
+
+  /* Sections to be discarded. */
+  /DISCARD/ : {
+    *(.exitcall.exit)
+    *(.exit.data)
+  }
+}