Fixes gcc '-Wunused-but-set-variable' warning:

drivers/net/ethernet/micrel/ksz884x.c: In function rx_proc:
drivers/net/ethernet/micrel/ksz884x.c:4981:6: warning: variable ‘rx_status’ set but not used [-Wunused-but-set-variable]

drivers/net/ethernet/micrel/ksz884x.c: In function netdev_get_ethtool_stats:
drivers/net/ethernet/micrel/ksz884x.c:6512:6: warning: variable ‘rc’ set but not used [-Wunused-but-set-variable]

these variable is never used, so remove it.
Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>