Blackfin arch: fix bug - crashes in tcp_v4_send_reset

Michael says that some bugs are crashes in tcp_v4_send_reset.
There's a missing clobber of "CC" in our checksum assembly
statement; fixing this makes the generated code look much saner.
Signed-off-by: NBernd Schmidt <bernds_cb1@t-online.de>
Signed-off-by: NBryan Wu <cooloney@kernel.org>

arch/blackfin/include/asm/checksum.h

@@ -78,7 +78,8 @@ csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
                  "%0 = %0 + %4;\n\t"
                  "NOP;\n\t"
  		 : "=d" (sum)
-		 : "d" (daddr), "d" (saddr), "d" ((ntohs(len)<<16)+proto*256), "d" (1), "0"(sum));
+		 : "d" (daddr), "d" (saddr), "d" ((ntohs(len)<<16)+proto*256), "d" (1), "0"(sum)
+		 : "CC");
 
 	return (sum);
 }