thermal/drivers/int340x: processor_thermal: Suppot 64 bit RFIM responses

Some of the RFIM mail box command returns 64 bit values. So enhance
mailbox interface to return 64 bit values and use them for RFIM
commands.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Fixes: 5d6fbc96 ("thermal/drivers/int340x: processor_thermal: Export additional attributes")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>