drm/amd/powerplay: Fix code error for translating int type to bool type correctly

Fix code error to support value < 0 or > 1.

Signed-off-by: Chengming Gui <Jack.Gui@amd.com>
Reviewed-by: Hawking Zhang <hawking.zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>