wifi: ath9k: htc_hst: free skb in ath9k_htc_rx_msg() if there is no callback function

wifi: ath9k: htc_hst: free skb in ath9k_htc_rx_msg() if there is no callback function

[ Upstream commit 9a831256128effadd9ebb782e9c875ac3bbe9134 ]

It is stated that ath9k_htc_rx_msg() either frees the provided skb or
passes its management to another callback function. However, the skb is
not freed in case there is no another callback function, and Syzkaller was
able to cause a memory leak. Also minor comment fix.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: ee12d32d37b7 ("ath9k_htc: Support for AR9271 chipset.")
Reported-by: syzbot+e008dccab31bd3647609@syzkaller.appspotmail.com
Reported-by: syzbot+6692c72009680f7c4eb2@syzkaller.appspotmail.com
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20230104123546.51427-1-pchelkin@ispras.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>