P2P: Fix pending-sta-scan processing for concurrent operation cases

P2P: Fix pending-sta-scan processing for concurrent operation cases

If two P2P_FIND commands and a station mode SCAN command are issued in a
sequence with the second P2P_FIND and SCAN commands started before the
initial scan from the first P2P_FIND command has completed,
sta_scan_pending may be left set without an automatic way of getting it
cleared. This can get P2P search stuck if no further station mode scan
operations are run.

Fix this by clearing the sta_scan_pending flag whenever station mode scans
are stopped due to no enabled networks resulting in INACTIVE mode getting
entered. In addition, avoid setting sta_scan_pending flag when a special
scan_res_handler is set so that this does not get enabled on the P2P
Device interface during a P2P search operation.

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>