The firmware code cannot cope with requests to remove BSS indices that have
not previously been added. This primarily happens when the device is
suspended and then resumed. ieee80211_reconfig() then calls into
wcn36xx_bss_info_changed() with an empty bssid and BSS_CHANGED_BSSID set,
which subsequently leads to a firmware crash:

[   43.647928] qcom-wcnss-pil a204000.wcnss: fatal error received: halMsg.c:4964:halMsg_DelBss: Invalid BSSIndex 0
[   43.647959] remoteproc remoteproc0: crash detected in a204000.wcnss: type fatal error

To fix this, set bss_index to WCN36XX_HAL_BSS_INVALID_IDX for all bss
that have not been configured in the firmware, and don't call into the
firmware with invalid indices.
Signed-off-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>