drm/amd/powerplay: enable powerplay as default on CZ/ST

Enable powerplay as default on Carrizo and Stoney. And it can be
disabled with amdgpu.powerplay=0.
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Huang Rui <ray.huang@amd.com>
Cc: Rex Zhu <Rex.Zhu@amd.com>
Cc: Flora Cui <Flora.Cui@amd.com>
Cc: Ken Wang <Qingqing.Wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_powerplay.c

@@ -109,11 +109,9 @@ static int amdgpu_pp_early_init(void *handle)
 	case CHIP_TONGA:
 	case CHIP_FIJI:
 	case CHIP_TOPAZ:
-		adev->pp_enabled = (amdgpu_powerplay == 0) ? false : true;
-		break;
 	case CHIP_CARRIZO:
 	case CHIP_STONEY:
-		adev->pp_enabled = (amdgpu_powerplay > 0) ? true : false;
+		adev->pp_enabled = (amdgpu_powerplay == 0) ? false : true;
 		break;
 	/* These chips don't have powerplay implemenations */
 	case CHIP_BONAIRE: