wifi: mac80211: fix MPDU length parsing for EHT 5/6 GHz

The MPDU length is only configured using the EHT capabilities element on
2.4 GHz. On 5/6 GHz it is configured using the VHT or HE capabilities
respectively.

Fixes: cf00792 ("wifi: mac80211: parse A-MSDU len from EHT capabilities")
Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@intel.com>
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20250311121704.0634d31f0883.I28063e4d3ef7d296b7e8a1c303460346a30bf09c@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/eht.c

@@ -2,7 +2,7 @@
 /*
  * EHT handling
  *
- * Copyright(c) 2021-2024 Intel Corporation
+ * Copyright(c) 2021-2025 Intel Corporation
  */
 
 #include "ieee80211_i.h"
@@ -76,6 +76,13 @@ ieee80211_eht_cap_ie_to_sta_eht_cap(struct ieee80211_sub_if_data *sdata,
 	link_sta->cur_max_bandwidth = ieee80211_sta_cap_rx_bw(link_sta);
 	link_sta->pub->bandwidth = ieee80211_sta_cur_vht_bw(link_sta);
 
+	/*
+	 * The MPDU length bits are reserved on all but 2.4 GHz and get set via
+	 * VHT (5 GHz) or HE (6 GHz) capabilities.
+	 */
+	if (sband->band != NL80211_BAND_2GHZ)
+		return;
+
 	switch (u8_get_bits(eht_cap->eht_cap_elem.mac_cap_info[0],
 			    IEEE80211_EHT_MAC_CAP0_MAX_MPDU_LEN_MASK)) {
 	case IEEE80211_EHT_MAC_CAP0_MAX_MPDU_LEN_11454: