ath11k: add thermal sensor device support

Temperature sensor generates electrical analog voltage from temperature
of each chain. The analog voltage is converted to digital value through
ADC. For reading temperature values fom user space, hw monitoring device
is used.

Whenever the user requests for current temperature, the driver sends WMI
command and wait for response. For reading temperature,

cat /sys/class/ieee80211/phy*/device/hwmon/hwmon2/temp1_input

Signed-off-by: Pradeep Kumar Chitrapu <pradeepc@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>