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/udivsi3.S b/arch/blackfin/lib/udivsi3.S
index d39a129..58fd96d 100644
--- a/arch/blackfin/lib/udivsi3.S
+++ b/arch/blackfin/lib/udivsi3.S
@@ -296,3 +296,5 @@
   R1 = R0 - R3;
   IF CC R0 = R1;
   RTS;
+
+ENDPROC(___udivsi3)