thermal/int340x_thermal: Export GDDV

Implementing DPTF properly requires making use of firmware-provided
information associated with the INT3400 device. Calling GDDV provides a
buffer of information which userland can then interpret to determine
appropriate DPTF policy.

Conflicts:
	drivers/thermal/intel/int340x_thermal/int3400_thermal.c

Signed-off-by: Matthew Garrett <mjg59@google.com>
Tested-by: Pandruvada, Srinivas <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20200414020953.255364-1-matthewgarrett@google.com