[IA64] strcpy returns NULL pointer and not destination pointer

Bob Picco noted that 6edfba1b33
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>

arch/ia64/lib/memcpy_mck.S

@@ -6,7 +6,9 @@
  *	in1:	source address
  *	in2:	number of bytes to copy
  * Output:
- * 	0 if success, or number of byte NOT copied if error occurred.
+ *	for memcpy:    return dest
+ * 	for copy_user: return 0 if success,
+ *		       or number of byte NOT copied if error occurred.
  *
  * Copyright (C) 2002 Intel Corp.
  * Copyright (C) 2002 Ken Chen <kenneth.w.chen@intel.com>
@@ -73,6 +75,7 @@ GLOBAL_ENTRY(memcpy)
 	and	r28=0x7,in0
 	and	r29=0x7,in1
 	mov	f6=f0
+	mov	retval=in0
 	br.cond.sptk .common_code
 	;;
 END(memcpy)
@@ -84,7 +87,7 @@ GLOBAL_ENTRY(__copy_user)
 	mov	f6=f1
 	mov	saved_in0=in0	// save dest pointer
 	mov	saved_in1=in1	// save src pointer
-	mov	saved_in2=in2	// save len
+	mov	retval=r0	// initialize return value
 	;;
 .common_code:
 	cmp.gt	p15,p0=8,in2	// check for small size
@@ -92,7 +95,7 @@ GLOBAL_ENTRY(__copy_user)
 	cmp.ne	p14,p0=0,r29	// check src alignment
 	add	src0=0,in1
 	sub	r30=8,r28	// for .align_dest
-	mov	retval=r0	// initialize return value
+	mov	saved_in2=in2	// save len
 	;;
 	add	dst0=0,in0
 	add	dst1=1,in0	// dest odd index