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>

diff --git a/arch/blackfin/lib/umulsi3_highpart.S b/arch/blackfin/lib/umulsi3_highpart.S
index aac8218..67b7993 100644
--- a/arch/blackfin/lib/umulsi3_highpart.S
+++ b/arch/blackfin/lib/umulsi3_highpart.S
@@ -21,3 +21,5 @@
 	R1 = PACK(R1.l,R0.h);
 	R0 = R1 + R2;
 	RTS;
+
+.size ___umulsi3_highpart, .-___umulsi3_highpart