[ARM] Remove RETINSTR macro

RETINSTR is a left-over from the days when we had 26-bit and
32-bit CPU support integrated into the same tree.  Since this
is no longer the case, we can now remove RETINSTR.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/lib/memchr.S b/arch/arm/lib/memchr.S
index ac34fe5..e7ab1ea 100644
--- a/arch/arm/lib/memchr.S
+++ b/arch/arm/lib/memchr.S
@@ -22,4 +22,4 @@
 	bne	1b
 	sub	r0, r0, #1
 2:	movne	r0, #0
-	RETINSTR(mov,pc,lr)
+	mov	pc, lr