ath11k: Add support for STA to handle beacon miss

When AP goes down without any indication to STA, firmware detects
missing beacon, and sends wmi roam event with reason BEACON_MISS
to the host.

Added support for STA mode to trigger disassociation from AP,
on receiving this event from firmware.

Tested-on: IPQ8074 hw2.0 AHB WLAN.HK.2.4.0.1-01717-QCAHKSWPL_SILICONZ-1
Tested-on: QCA6390 hw2.0 PCI WLAN.HST.1.0.1-01740-QCAHSTSWPLZ_V2_TO_X86-1

Signed-off-by: Lavanya Suresh <lavaks@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1614340859-28867-1-git-send-email-lavaks@codeaurora.org