wireless: allow 40 MHz on world roaming channels 12/13

commit 43c771a1963ab461a2f194e3c97fded1d5fe262f upstream.

When in world roaming mode, allow 40 MHz to be used
on channels 12 and 13 so that an AP that is, e.g.,
using HT40+ on channel 9 (in the UK) can be used.

Reported-by: Eddie Chapman <eddie@ehuk.net>
Tested-by: Eddie Chapman <eddie@ehuk.net>
Acked-by: Luis R. Rodriguez <mcgrof@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>