stmmac: fix Transmit FIFO flush operation

Fix the Transmit FIFO flush operation; it was
disabled while reworking the descriptor structures.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc drivers/net/stmmac/common.h
Simple merge

diff --cc drivers/net/stmmac/dwmac1000.h
Simple merge

diff --cc drivers/net/stmmac/dwmac1000_dma.c
Simple merge

diff --cc drivers/net/stmmac/dwmac_dma.h
Simple merge

diff --cc drivers/net/stmmac/dwmac_lib.c
Simple merge

diff --cc drivers/net/stmmac/enh_desc.c
Simple merge