[IA64] Fix memcpy_mck.S for current binutils

The current ia64 assembler complains about mismatching .proc/.endp pairs.
(Same patch also sent by H.J. Lu)

Signed-off-by: Andreas Schwab <[e-mail]>
Signed-off-by: Tony Luck <[e-mail]>

arch/ia64/lib/memcpy_mck.S

···
 	mov	f6=f0
 	br.cond.sptk .common_code
 	;;
+END(memcpy)
 GLOBAL_ENTRY(__copy_user)
 	.prologue
 // check dest alignment
···
 #undef B
 #undef C
 #undef D
-END(memcpy)
 
 /*
  * Due to lack of local tag support in gcc 2.x assembler, it is not clear which