wil6210: run-time PM when interface down

Allow run-time suspend when interface is down, keep card alive when
interface is up.
If driver is in wmi only or debug_fw mode run-time PM won't suspend.

Signed-off-by: Lazar Alexei <qca_ailizaro@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>