mac80211: reduce peer HE MCS/NSS to own capabilities

For VHT capbility, we do intersection of MCS and NSS for peers in
mac80211, to simplify drivers.

Add this for HE as well.

Signed-off-by: Wen Gong <wgong@codeaurora.org>
Link: https://lore.kernel.org/r/1609816120-9411-3-git-send-email-wgong@codeaurora.org


[reword commit message, style cleanups, fix endian annotations]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>