wil6210: Improve AP stop handling

Set resetting flag early when stopping AP to avoid
disconnect events as a result of disconnect command
sent during AP stop procedure.

Signed-off-by: Hamad Kadmany <qca_hkadmany@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>