Revert "drm/amd/display: disable S/G display on DCN 3.1.4"

This reverts commit 9aa1537.

This is fixed now so we can re-enable S/G display on DCN
3.1.4.

Reviewed-by: Yifan Zhang <yifan1.zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -1567,6 +1567,7 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
 				init_data.flags.gpu_vm_support = true;
 			break;
 		case IP_VERSION(3, 0, 1):
+		case IP_VERSION(3, 1, 4):
 		case IP_VERSION(3, 1, 6):
 			init_data.flags.gpu_vm_support = true;
 			break;