drm/amd/powerplay: expose current hotspot and memory temperatures V2

Two new hwmon interfaces(temp2_input and temp3_input) are added.
They are supported on SOC15 dGPUs only.

- V2: correct thermal sensor output

Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>