wifi: mt76: fix argument to ieee80211_is_first_frag()

mainline inclusion
from mainline-v7.2-rc1
category: bugfix

ieee80211_is_first_frag() operates on the seq_ctrl not the frame_control
header field. Pass the correct one in; otherwise the results may vary.

Sponsored by: The FreeBSD Foundation
Fixes: 30ce7f4 ("mt76: validate rx CCMP PN")
Link: https://cgit.freebsd.org/src/commit/sys/contrib/dev/mediatek/mt76/mac80211.c?id=c67fd35e58c6ee1e19877a7fe5998885683abedc
Signed-off-by: Bjoern A. Zeeb <bz@FreeBSD.org>
Link: https://patch.msgid.link/83s4psnr-popo-8789-757o-npr2n9n7rs2o@SerrOFQ.bet
Signed-off-by: Felix Fietkau <nbd@nbd.name>
(cherry picked from commit 5832743279da8c6ae72f715bad2f7141eca6f4b8)
Signed-off-by: Wentao Guan <guanwentao@uniontech.com>

Author: Bjoern A. Zeeb

drivers/net/wireless/mediatek/mt76/mac80211.c

@@ -1162,7 +1162,7 @@ mt76_check_ccmp_pn(struct sk_buff *skb)
 		 * All further fragments will be validated by mac80211 only.
 		 */
 		if (ieee80211_is_frag(hdr) &&
-		    !ieee80211_is_first_frag(hdr->frame_control))
+		    !ieee80211_is_first_frag(hdr->seq_ctrl))
 			return;
 	}