net/wireless: enable wiphy device to suspend/resume asynchronously

Now, PM core supports asynchronous suspend/resume mode for devices
during system suspend/resume, and the power state transition of one
device may be completed in separate kernel thread. PM core ensures
all power state transition timing dependency between devices. This
patch enables wiphy device to suspend/resume asynchronously. This can
take advantage of multicore and improve system suspend/resume speed.

Signed-off-by: Zhonghui Fu <zhonghui.fu@linux.intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>