Bluetooth: Finish implementation for Rec RR (P=1) on ERTM

Now the code handles the case under SREJ_SENT state.

Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: João Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>