ath10k: add ath10k_htt_rx_amsdu_allowed function

Introduce ath10k_htt_rx_amsdu_allowed() function, that
group code for checking if skip amsdu packets.

Signed-off-by: Janusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>