wifi: rtw89: add thermal protection

To prevent chip overheating, reduce TX duty as the mechanism of thermal
protection. When temperature is raising over a threshold, send a firmware
command to reduce TX duty. If temperature is still raising, higher level
is adopted to have lower active duration.

The equation and unit of thermal values are different from chip to chip,
so define constant thresholds of thermal value to corresponding absolute
temperature of 110 and 120 degree Celsius.

Latter patch will decide which thermal threshold is adopted, and current
is still not enable thermal protection.

For debugging, add a flag to disable_dm that thermal protection can be
disabled to clarify low throughput in field.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20241016133735.7571-2-pkshih@realtek.com