mt76: fix tx status reporting for non-probing frames

On MT76x2, the hardware does not report tx status in the FIFO register,
if the packet id is 0.
Change the allocation of packet IDs to use 0 for no-ack packets, 1 for
non-probing packets and 2-255 for packets with tx status requested.
Fixes rate control issues

Signed-off-by: Felix Fietkau <nbd@nbd.name>