ath10k: implement device recovery

Restart the hardware if FW crashes.

If FW crashes during recovery we leave the
hardware in a "wedged" state to avoid recursive
recoveries.

When in "wedged" state userspace may bring
interfaces down (to issue stop()) and then bring
one interface (to issue start()) to reload
hardware manually.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>