The Extended Channel Switching capability bit in the extended
capabilities element must be set if the driver supports CSA on
non-beaconing interfaces.

Since this capability needs to be set during driver registration, the
extended_capabiliities global variable needs to be moved to the local
structure so that it can be modified.
Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>