ANDROID: GKI: Add devm_thermal_of_virtual_sensor_register API.

This API registers a virtual thermal sensor.

Test: build
Bug: 149945768
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>
Change-Id: I72b29b4296d9be949d096913471153b596c67e1f
[hridya: commit amended to only pull in the API implementation and code
needed to build it.]
(cherry picked commit from 8a12149c264c7b871932ad90f76e5981452bb4bb)
Signed-off-by: Hridya Valsaraju <hridya@google.com>