rtw88: 8822c: add ieee80211_ops::hw_scan

Declare this function allows us to use customized scanning policy.
By doing so we can be more time efficient on each scan. In order to
make existing coex mechanism work as usual, firmware notifies driver
on each channel switch event, then decide antenna ownership based on
the current channel/band. Do note that this new mechanism affects
throughput more than the sw_scan we used to have, but the overall
average throughput is not affected since each scan take less time.
Since the firmware size is limited, we only support probe requests
with custom IEs length under 128 bytes for now, if any user space
tools requires more than that, we'll introduce related changes
afterwards. For backward compatibility, we fallback to sw_scan when
using older firmware that does not support this feature.

Signed-off-by: Po-Hao Huang <phhuang@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/20211221085010.39421-1-pkshih@realtek.com