drm/amd/powerplay: move bootup value before read pptable from vbios

In navi10, we need read the pp_table_id from bootup value, then decide whether
use load the soft pptable.

Signed-off-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>