mac80211: remove queue stop on rate control update

We currently stop the queue when changing the rate
control between 20/40 MHz in the BSS. This seems to
have been necessary when we actually changed the
channel, but now that we just update the station it
doesn't seem right any more. Remove it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>