Replace bx lr with update of pc from the stack.

When there is arm assembler of this format:

ldmxx sp!, {..., lr} or pop {..., lr}
bx lr

It can be replaced with:

ldmxx sp!, {..., pc} or pop {..., pc}

Change-Id: Ic27048c52f90ac4360ad525daf0361a830dc22a3
diff --git a/libc/arch-arm/generic/bionic/memcpy.S b/libc/arch-arm/generic/bionic/memcpy.S
index ea5a399..65cba4c 100644
--- a/libc/arch-arm/generic/bionic/memcpy.S
+++ b/libc/arch-arm/generic/bionic/memcpy.S
@@ -194,8 +194,7 @@
 
         /* we're done! restore everything and return */
 1:      ldmfd       sp!, {r5-r11}
-        ldmfd       sp!, {r0, r4, lr}
-        bx          lr
+        ldmfd       sp!, {r0, r4, pc}
 
         /********************************************************************/
 
@@ -385,8 +384,7 @@
 
         /* we're done! restore sp and spilled registers and return */
         add         sp,  sp, #28
-        ldmfd       sp!, {r0, r4, lr}
-        bx          lr
+        ldmfd       sp!, {r0, r4, pc}
 END(memcpy)
 
         // Only reached when the __memcpy_chk check fails.