ieee80211: Add new A-MPDU factor macro for HE 6 GHz peer caps

Add IEEE80211_HE_6GHZ_MAX_AMPDU_FACTOR as per IEEE Std 802.11ax-2021,
9.4.2.263 to use for peer max A-MPDU factor in 6 GHz band.

Signed-off-by: Pradeep Kumar Chitrapu <pradeepc@codeaurora.org>
Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210913175510.193005-1-jouni@codeaurora.org