Revert "drm/amd/amdgpu: Disable GFX_PG on Carrizo until compute issues solved"

Re-enable GFX PG.  It's working properly with MEC now that KIQ is
enabled.
Reviewed-by: Samuel  Li <samuel.li@amd.com>

This reverts commit e9ef19aa1bdeac380662a112f1d03a7c3477527f.

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

@@ -1073,7 +1073,7 @@ static int vi_common_early_init(void *handle)
 		/* rev0 hardware requires workarounds to support PG */
 		adev->pg_flags = 0;
 		if (adev->rev_id != 0x00 || CZ_REV_BRISTOL(adev->pdev->revision)) {
-			adev->pg_flags |=
+			adev->pg_flags |= AMD_PG_SUPPORT_GFX_PG |
 				AMD_PG_SUPPORT_GFX_SMG |
 				AMD_PG_SUPPORT_GFX_PIPELINE |
 				AMD_PG_SUPPORT_CP |