ERTM spec mandates that after receive a P-bit we shall send an F-bit in
response. This patch fixes this for retransmitted packets, on
retransmitting we were missing to check for a pending F-bit to be sent.
Also we were missing some annotation to send a F-bit.
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: NJoão Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>