Support setting HE GI and LTF values to the kernel via nl80211.
We currently only support some GI and LTF values settings.

The command example is:
  iw wlan0 set bitrates he-gi-2.4 0.8 he-ltf-2.4 2
Signed-off-by: Kuan-Chung Chen <damon.chen@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220912070014.10018-2-pkshih@realtek.com