[openwrt/openwrt] mac80211: fix HT40 mode for 6G band

[LEDE Commits]

nbd pushed a commit to openwrt/openwrt.git, branch openwrt-21.02:
https://git.openwrt.org/4a70b93f2d0bd325740ed3a197ca78118cdf7279

commit 4a70b93f2d0bd325740ed3a197ca78118cdf7279
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Mon Aug 16 10:05:14 2021 +0200

    mac80211: fix HT40 mode for 6G band
    
    The channel offset used for VHT segment calculation was missing for HT
    
    Signed-off-by: Felix Fietkau <nbd at nbd.name>
    (cherry-picked from commit a0d81ba0d5e9d055c55b5e478cb913c217122317)
---
 package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh b/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh
index c4f843e5bb..07e0758c4f 100644
--- a/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh
+++ b/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh
@@ -148,6 +148,9 @@ mac80211_hostapd_setup_base() {
 	[ "$noscan" -gt 0 ] && hostapd_noscan=1
 	[ "$tx_burst" = 0 ] && tx_burst=
 
+	chan_ofs=0
+	[ "$band" = "6g" ] && chan_ofs=1
+
 	ieee80211n=1
 	ht_capab=
 	case "$htmode" in
@@ -155,7 +158,7 @@ mac80211_hostapd_setup_base() {
 		HT40*|VHT40|VHT80|VHT160|HE40|HE80|HE160)
 			case "$hwmode" in
 				a)
-					case "$(( ($channel / 4) % 2 ))" in
+					case "$(( (($channel / 4) + $chan_ofs) % 2 ))" in
 						1) ht_capab="[HT40+]";;
 						0) ht_capab="[HT40-]";;
 					esac
@@ -224,8 +227,6 @@ mac80211_hostapd_setup_base() {
 	enable_ac=0
 	vht_oper_chwidth=0
 	vht_center_seg0=
-	chan_ofs=0
-	[ "$band" = "6g" ] && chan_ofs=1
 
 	idx="$channel"
 	case "$htmode" in