The firmware of QCA6174/QCA9377 already support the feature, just enable
it to be able to handle the get_temperature command and process the event.

You can read the temperature by using the hwmon interface,

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

Verified with the following hardware and software combination,
QCA6174, only firmware-4.bin doesn't support this, otherwise all support.
QCA9377, all the firmwares upstreamed support this command
Signed-off-by: Ryan Hsu <ryanhsu@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>