wifi: rtw89: rfk: add H2C command to trigger TXGAPK

TXGAPK stands for TX power gap calibration. Use this calibration to
compensate TX power gap to output expected power.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240202030642.108385-8-pkshih@realtek.com