wil6210: ensure P2P device is stopped before removing interface

User space can remove the P2P management interface while it is active
(for example, while listen/search is active) and this can cause
a crash. Ensure the P2P device is fully stopped before removing.

Signed-off-by: Lior David <qca_liord@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>