ath11k: purge rx pktlog when entering WoW

This change is to purge rx pktlog when entering WoW and reap
the mon_status buffer to keep it empty. When leaving WoW, host
restarts the reap timer. In WoW state, it's not allowed to feed
into mon_status rings per firmware team's recommendation.

Tested-on: QCA6390 hw2.0 PCI WLAN.HST.1.0.1-01740-QCAHSTSWPLZ_V2_TO_X86-1

Signed-off-by: Carl Huang <quic_cjhuang@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/1644308006-22784-5-git-send-email-quic_cjhuang@quicinc.com