drm/vmwgfx: Handle possible ENOMEM in vmw_stdu_connector_atomic_check

Handle unlikely ENOMEN condition and other errors in
vmw_stdu_connector_atomic_check.

Signed-off-by: Ian Forbes <ian.forbes@broadcom.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Fixes: 75c3e8a ("drm/vmwgfx: Trigger a modeset when the screen moves")
Reviewed-by: Zack Rusin <zack.rusin@broadcom.com>
Reviewed-by: Martin Krastev <martin.krastev@broadcom.com>
Signed-off-by: Zack Rusin <zack.rusin@broadcom.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240809183756.27283-1-ian.forbes@broadcom.com

Author: en4bz

drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c

@@ -886,6 +886,10 @@ static int vmw_stdu_connector_atomic_check(struct drm_connector *conn,
 	struct drm_crtc_state *new_crtc_state;
 
 	conn_state = drm_atomic_get_connector_state(state, conn);
+
+	if (IS_ERR(conn_state))
+		return PTR_ERR(conn_state);
+
 	du = vmw_connector_to_stdu(conn);
 
 	if (!conn_state->crtc)