wifi: mac80211: set band information only for non-MLD when probing stations using...

wifi: mac80211: set band information only for non-MLD when probing stations using NULL frame

Currently, when sending a NULL frame to probe a station, the band
information is derived from the chanctx_conf in the mac80211 vif's
bss_conf. However, for AP MLD, chanctx_conf is not assigned to the
vif's bss_conf; instead it is assigned on a per-link basis. As a result,
for AP MLD, sending a NULL packet to probe will trigger a warning.

WARNING: net/mac80211/cfg.c:4635 at ieee80211_probe_client+0x1a8/0x1d8 [mac80211], CPU#2: hostapd/244
Call trace:
 ieee80211_probe_client+0x1a8/0x1d8 [mac80211] (P)
 nl80211_probe_client+0xac/0x170 [cfg80211]
 genl_family_rcv_msg_doit+0xc8/0x134
 genl_rcv_msg+0x200/0x280
 netlink_rcv_skb+0x38/0xf0
 genl_rcv+0x34/0x48
 netlink_unicast+0x314/0x3a0
 netlink_sendmsg+0x150/0x390
 ____sys_sendmsg+0x1f4/0x21c
 ___sys_sendmsg+0x98/0xc0
 __sys_sendmsg+0x74/0xcc
 __arm64_sys_sendmsg+0x20/0x34
 invoke_syscall.constprop.0+0x4c/0xd0
 do_el0_svc+0x3c/0xd0
 el0_svc+0x28/0xc0
 el0t_64_sync_handler+0x98/0xdc
 el0t_64_sync+0x154/0x158
---[ end trace 0000000000000000 ]---

For NULL packets sent to probe stations, set the band information only
for non-MLD, since MLD transmissions does not rely on band.

Signed-off-by: Suraj P Kizhakkethil <suraj.kizhakkethil@oss.qualcomm.com>
Link: https://patch.msgid.link/20260213100126.1414398-2-suraj.kizhakkethil@oss.qualcomm.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>