ieee80211: add definition of regulatory info in 6 GHz operation information

IEEE Std 802.11ax™-2021 added regulatory info subfield in HE operation
element, add it to the header file.

Signed-off-by: Wen Gong <wgong@codeaurora.org>
Link: https://lore.kernel.org/r/20210820122041.12157-3-wgong@codeaurora.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>