drm/vmwgfx: Return -ENOENT when a mode object can't be found

Let's be a bit more consistent with our error values.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index fc43c06..ecb3d86 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -1508,7 +1508,7 @@
 
 	obj = drm_mode_object_find(dev, arg->crtc_id, DRM_MODE_OBJECT_CRTC);
 	if (!obj) {
-		ret = -EINVAL;
+		ret = -ENOENT;
 		goto out;
 	}