Variable rc is set to zero but this value is never read as it is
overwritten with a new value later on, hence it is a redundant
assignment and can be removed.

Cleans up the following clang-analyzer warning:

net/smc/af_smc.c:1079:3: warning: Value stored to 'rc' is never read
[clang-analyzer-deadcode.DeadStores].
Reported-by: NAbaci Robot <abaci@linux.alibaba.com>
Signed-off-by: NJiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>