cfg80211: add an option to disable processing country IEs

Certain vendors may want to disable the processing of
country IEs so that they can continue using the regulatory
domain the driver or user has set.  Currently there is no
way to stop the core from processing country IEs, so add
support to the core to ignore country IE hints.

Cc: Mihir Shete <smihir@qti.qualcomm.com>
Cc: Henri Bahini <hbahini@qca.qualcomm.com>
Cc: Tushnim Bhattacharyya <tushnimb@qca.qualcomm.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>