nl80211: Add regulatory wmm_limit to hostapd_channel_data

nl80211: Add regulatory wmm_limit to hostapd_channel_data

ETSI EN 301 893 v2.1.1 (2017-05) standard defines a new channel access
mechanism that all devices (WLAN and LAA) need to comply with.
In previous versions the device was allowed by ETSI to implement
802.11 channel access mechanism based on a set of priority classes
which are taken from 802.11. According of the new standard there
might be some exceptions which require ETSI countries to follow
more restrictive rules. In such a case the AP's wmm IE need to
comply with ETSI limitation. To be able to do so the regulatory
domain passes the new limitation values if needed.
Implement this, by storing it and use it to calculate the new
WMM parameters.

This commit adds determination of regulator limitations to
NL80211_CMD_GET_WIPHY processing so that the information is available
for upper layer implementation to use later when constructing WMM
element.

Signed-off-by: Haim Dreyfuss <haim.dreyfuss@intel.com>