cxgb4: make symbol pedits static

Fixes the following sparse warning:

drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c:46:27: warning:
 symbol 'pedits' was not declared. Should it be static?

Fixes: 27ece1f3

 ("cxgb4: add tc flower support for ETH-DMAC rewrite")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>