powerpc: move math-emu over to arch/powerpc

Towards the goal of having arch/powerpc not build anything over in arch/ppc
move math-emu over.  Also, killed some references to arch/ppc/ in the
arch/powerpc Makefile which should belong in drivers/ when the particular
sub-arch's move over to arch/powerpc.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/math-emu/fabs.c

@@ -0,0 +1,18 @@
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <asm/uaccess.h>
+
+int
+fabs(u32 *frD, u32 *frB)
+{
+	frD[0] = frB[0] & 0x7fffffff;
+	frD[1] = frB[1];
+
+#ifdef DEBUG
+	printk("%s: D %p, B %p: ", __FUNCTION__, frD, frB);
+	dump_double(frD);
+	printk("\n");
+#endif
+
+	return 0;
+}