rules: Tag DRM render nodes with xaccess

When systemd is compiled with group-render-mode=0660, only the active seat
gets access to the render devices through uaccess. Remote desktop sessions
like gnome-remote-desktop would be left with no hardware rendering, because
those sessions are not associated with a seat.

Tag the render nodes with "xaccess" so that access is also granted to remote
sessions created with XDG_SESSION_EXTRA_DEVICE_ACCESS=1

rules.d/70-uaccess.rules.in

@@ -46,7 +46,7 @@ SUBSYSTEM=="firewire", TEST=="units", ENV{IEEE1394_UNIT_FUNCTION_VIDEO}=="1", TA
 SUBSYSTEM=="drm", KERNEL=="card*", TAG+="uaccess"
 {% if GROUP_RENDER_UACCESS %}
 # DRI render nodes
-SUBSYSTEM=="drm", KERNEL=="renderD*", TAG+="uaccess"
+SUBSYSTEM=="drm", KERNEL=="renderD*", TAG+="uaccess", TAG+="xaccess"
 {% endif %}
 {% if DEV_KVM_UACCESS %}
 # KVM