[SPARC64]: Mark __ex_table section correctly.

We must use the "a" (allocate) attribute every time we
emit an entry into the __ex_table section.

For consistency, use "a" instead of #alloc which is some
Solaris compat cruft GNU as provides on Sparc.

Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc64/lib/strlen_user.S

@@ -85,7 +85,7 @@ __strnlen_user:
         retl
          clr    %o0
 
-	.section __ex_table,#alloc
+	.section __ex_table,"a"
 	.align	4
 
 	.word	10b, 30b