carl9170: replace GFP_ATOMIC in ampdu_action, it can sleep

Since ~2010, the driver is allowed to sleep in the ampdu_action
callback thanks to:
commit 85ad181e ("mac80211: allow drivers to sleep in ampdu_action")

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/0036538d0933626a1a5eb2c2c3935cf173028926.1646250537.git.chunkeey@gmail.com