When wlan interface is up, 11d scan is sent to the firmware, and the
firmware needs to spend couple of seconds to complete the 11d scan. If
immediately a normal scan from user space arrives to ath11k, then the
normal scan request is also sent to the firmware, but the scan started
event will be reported to ath11k until the 11d scan complete. When timed
out for the scan started in ath11k, ath11k stops the normal scan and the
firmware reports WMI_SCAN_EVENT_DEQUEUED to ath11k for the normal scan.
ath11k has no handler for the event and then timed out for the scan
completed in ath11k_scan_stop(), and ath11k prints the following error
message.

[ 1491.604750] ath11k_pci 0000:02:00.0: failed to receive scan abort comple: timed out
[ 1491.604756] ath11k_pci 0000:02:00.0: failed to stop scan: -110
[ 1491.604758] ath11k_pci 0000:02:00.0: failed to start hw scan: -110

Add a handler for WMI_SCAN_EVENT_DEQUEUED and then complete the scan to
get rid of the above error message.

Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-01720.1-QCAHSPSWPL_V1_V2_SILICONZ_LITE-1
Signed-off-by: Wen Gong <wgong@codeaurora.org>
Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210914164226.38843-1-jouni@codeaurora.org