cxgb4: Add sge ec context flush service

Add function to flush the sge ec context cache, and utilize
this new function in the driver

Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc drivers/net/ethernet/chelsio/cxgb4/cxgb4.h
Simple merge

diff --cc drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
Simple merge

diff --cc drivers/net/ethernet/chelsio/cxgb4/t4_hw.c
Simple merge

diff --cc drivers/net/ethernet/chelsio/cxgb4/t4fw_api.h
Simple merge