drm/amdgpu: No need to check gfxoff status after enable gfxoff feature

smu_send_smc_msg(smu, SMU_MSG_AllowGfxOff) Just turn on a switch.

As to when GPU get into "GFXoff" will be up to drawing load.

So we can not sure which state GPU should be in after enable gfxoff
feature.
Signed-off-by: chen gong <curry.gong@amd.com>
Acked-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Kevin Wang <kevin1.wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/powerplay/smu_v12_0.c

@@ -244,15 +244,6 @@ static int smu_v12_0_gfx_off_control(struct smu_context *smu, bool enable)
 	if (enable) {
 		ret = smu_send_smc_msg(smu, SMU_MSG_AllowGfxOff);
 
-		/* confirm gfx is back to "off" state, timeout is 5 seconds */
-		while (!(smu_v12_0_get_gfxoff_status(smu) == 0)) {
-			msleep(10);
-			timeout--;
-			if (timeout == 0) {
-				DRM_ERROR("enable gfxoff timeout and failed!\n");
-				break;
-			}
-		}
 	} else {
 		ret = smu_send_smc_msg(smu, SMU_MSG_DisallowGfxOff);