igb: add ICR_RXDW

IGB uses RXDW ICR bit to indicate that rx descriptor has been written
back. This is the same as RXT0 bit in older HW.

Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
Signed-off-by: Jason Wang <jasowang@redhat.com>
2 files changed