wil6210: detect scan timeouts

If scan has not finished in some reasonable time (10sec), interpret it as
if firmware error occurs but was not reported. Firmware should report
scan completion for every scan request, so it is error condition indeed.
Perform firmware recovery procedure.

Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>