rtw89: handle 6G band if supported by a chipset

rtw89: handle 6G band if supported by a chipset

For next chipset which can support 6G band, we add the handling
of ieee80211_supported_band for 6G band in advance. And a bitmap,
support_bands, is added to rtw89_chip_info to declare which
NL80211_BAND_* are supported. With the chipset's declaration,
we register the corresponding instances of ieee80211_supported_band
with wiphy.

Signed-off-by: Zong-Zhe Yang <kevin_yang@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/20220113011042.6705-1-pkshih@realtek.com