cfg80211: allow specifying a reason for hw_rfkill

rfkill now allows to report a reason for the hw_rfkill state.
Allow cfg80211 drivers to specify this reason.
Keep the current API to use the default reason
(RFKILL_HARD_BLOCK_SIGNAL).

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Link: https://lore.kernel.org/r/20210322204633.102581-4-emmanuel.grumbach@intel.com


Signed-off-by: Johannes Berg <johannes.berg@intel.com>