Bluetooth: Completes the I-frame tx_seq check logic on RECV

Add checks for invalid tx_seq and fixes the duplicated tx_seq check.

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