iwlwifi: resending QoS command when HT changes

"mac80211: Fix WMM driver queue configuration"
inadvertedly broke iwlwifi, because now mac80211
configures the QoS settings before assoc, and
therefore before HT. Thus, iwlwifi no longer told
the device about the HT setting, which it needs
to -- and thus throughput went down a lot. Fix
this by resending the QoS command to the device
not only when QoS/WMM settings change, but also
when HT changes.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>