rtw88: 8821c: add phy calibration

In order to get a better TX EVM, do calibration after association.

The calibration needed for 8821c is the IQK, which is done in the
firmware. Implement the rtw_chip_ops::phy_calibration() to trigger
firmware to calibrate.

Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Tzu-En Huang <tehuang@realtek.com>
Signed-off-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200616091625.26489-8-yhchuang@realtek.com