hwmon: (fam15h_power) Rename fam15h_power_is_internal_node0 function

We rename fam15h_power_is_internal_node0() function to
should_load_on_this_node(), because it may not be node0 from KV and
on, and they are single-node processors.

Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>