rtw88: 8821c: add power tracking

The TX power requires to be adjusted based on the thermal value.
The actual power will decrease if the thermal value raised, and
will increase if the thermal value lowered. Driver comapres the
thermal value, as moving averages. If it changes over a limit,
driver will modify the TX power index to compensate.

Implement rtw_chip_ops::pwr_track() for 8821c.
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/20200603094218.19942-3-yhchuang@realtek.com

drivers/net/wireless/realtek/rtw88/main.h

@@ -1466,6 +1466,7 @@ struct rtw_dm_info {
 	u8 thermal_avg[RTW_RF_PATH_MAX];
 	u8 thermal_meter_k;
 	s8 delta_power_index[RTW_RF_PATH_MAX];
+	s8 delta_power_index_last[RTW_RF_PATH_MAX];
 	u8 default_ofdm_index;
 	bool pwr_trk_triggered;
 	bool pwr_trk_init_trigger;

drivers/net/wireless/realtek/rtw88/rtw8821c.h

@@ -200,6 +200,7 @@ _rtw_write32s_mask(struct rtw_dev *rtwdev, u32 addr, u32 mask, u32 data)
 #define REG_TXSCALE_A	0xc1c
 #define REG_TXDFIR	0xc20
 #define REG_RXIGI_A	0xc50
+#define REG_TXAGCIDX	0xc94
 #define REG_TRSW	0xca0
 #define REG_RFESEL0	0xcb0
 #define REG_RFESEL8	0xcb4