drm/vmwgfx: Don't send drm sysfs hotplug events on initial master set

This may confuse user-space clients like plymouth that opens a drm
file descriptor as a result of a hotplug event and then generates a
new event...

Cc: <stable@vger.kernel.org>
Fixes: 5ea17348 ("drm/vmwgfx: Send a hotplug event at master_set")
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Deepak Rawat <drawat@vmware.com>

drivers/gpu/drm/vmwgfx/vmwgfx_drv.c

@@ -1239,7 +1239,13 @@ static int vmw_master_set(struct drm_device *dev,
 	}
 
 	dev_priv->active_master = vmaster;
-	drm_sysfs_hotplug_event(dev);
+
+	/*
+	 * Inform a new master that the layout may have changed while
+	 * it was gone.
+	 */
+	if (!from_open)
+		drm_sysfs_hotplug_event(dev);
 
 	return 0;
 }