LinuxKPI: 802.11: minor header updates

• add comments for enum values constantly looked up, and another one to a net80211 equivalent (should possibly re-define those in the future?)
• add another nl80211_sta_info flag
• add enum environment_cap used in cfg80211.h in the future.

(cherry picked from commit 69cc1630014b7c50f754f5d49cfd4ed2905a5c48)