iwmc3200wifi: Support unexpected reboot barker

We can receive unexpected reboot barker at any time, and we're supposed to
reset the whole device then.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>