[IA64] strcpy returns NULL pointer and not destination pointer

Bob Picco noted that 6edfba1b
dropped the -ffreestanding compiler flag from the top level
Makefile, which allows the compiler to substitute memcpy() in
places where strcpy() is used with a known size source string.
But the ia64 memcpy() returns 0 for success, and "bytes copied"
for failure.

Fix to return the address of the destination string (like
stdlibc version, and other architectures).  There are no
places where ia64 specific code makes use of the non-standard
return value.

Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>