PowerPC LE strcpy

PowerPC LE strcpy
http://sourceware.org/ml/libc-alpha/2013-08/msg00100.html

The strcpy changes for little-endian are quite straight-forward, just
a matter of rotating the last word differently.

I'll note that the powerpc64 version of stpcpy is just begging to be
converted to use 64-bit loads and stores..

	* sysdeps/powerpc/powerpc64/strcpy.S: Add little-endian support:
	* sysdeps/powerpc/powerpc32/strcpy.S: Likewise.
	* sysdeps/powerpc/powerpc64/stpcpy.S: Likewise.
	* sysdeps/powerpc/powerpc32/stpcpy.S: Likewise.