wifi: mac80211: don't use rate mask for offchannel TX either

In the Linux kernel, the following vulnerability has been resolved:

wifi: mac80211: don't use rate mask for offchannel TX either

Like the commit ab9177d83c04 ("wifi: mac80211: don't use rate mask for

scanning"), ignore incorrect settings to avoid no supported rate warning

reported by syzbot.

The syzbot did bisect and found cause is commit 9df66d5b9f45 ("cfg80211:

fix default HE tx bitrate mask in 2G band"), which however corrects

bitmask of HE MCS and recognizes correctly settings of empty legacy rate

plus HE MCS rate instead of returning -EINVAL.

As suggestions [1], follow the change of SCAN TX to consider this case of

offchannel TX as well.

[1] https://lore.kernel.org/linux-wireless/[email protected]/T/#m2ac2a6d2be06a37c9c47a3d8a44b4f647ed4f024