[PATCH] uml: x86_64 fixes

This fixes some x86_64 bugs -

- maybe_map returns -1 on error instead of 0, which is interpreted as
  physical address 0

- removed an include of ipc.h, which isn't needed

- fixed the calculation of signal frame location

- the signal delivery code is now immune to the stack expansion check

- added a missing include

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/um/kernel/syscall_kern.c

@@ -17,7 +17,6 @@
 #include "linux/utime.h"
 #include "asm/mman.h"
 #include "asm/uaccess.h"
-#include "asm/ipc.h"
 #include "kern_util.h"
 #include "user_util.h"
 #include "sysdep/syscalls.h"