BACKPORT: ieee80211: add HE ext EIDs and 6 GHz capability defines

Add the HE extended element IDs and the definitions for the
HE 6 GHz band capabilities element, from Draft 5.0.

Bug: 163110886

Link: https://lore.kernel.org/r/20200528213443.1a6689fe093f.Ifdc5400fb01779351354daf38663ebeea03c9ad9@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Change-Id: I1de902cc0c4b57c57308641fb87244b5b7eb23e4
(cherry picked from commit 8b30808d9be4183fab17f0b0e68eea88c94ff15a)
Signed-off-by: Vamsi Krishna <vamsin@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>