Blackfin arch: add proper ENDPROC()

add proper ENDPROC() to close out assembly functions
so size/type is set properly in the final ELF image

Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

arch/blackfin/lib/memcmp.S

@@ -107,4 +107,4 @@ ENTRY(_memcmp)
 	P3 = I1;
 	RTS;
 
-.size _memcmp,.-_memcmp
+ENDPROC(_memcmp)