gdm: do not rely on dev-tty7.device

Error message was:

[ TIME ] Timed out waiting for device dev-tty7.device.
[DEPEND] Dependency failed for Gnome Display Manager.

run tested on overo/xfce

Signed-off-by: Andreas Müller <schnitzeltony@googlemail.com>
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>

meta-systemd/meta-gnome/recipes-gnome/gdm/gdm/gdm.service

@@ -1,7 +1,6 @@
 [Unit]
 Description=Gnome Display Manager
-Requires=dev-tty7.device
-After=dev-tty7.device systemd-user-sessions.service
+After=systemd-user-sessions.service
 
 [Service]
 ExecStart=/usr/sbin/gdm -nodaemon

meta-systemd/meta-gnome/recipes-gnome/gdm/gdm_2.32.2.bbappend

@@ -1,7 +1,7 @@
 # look for files in the layer first
 FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
 
-PRINC := "${@int(PRINC) + 2}"
+PRINC := "${@int(PRINC) + 3}"
 
 inherit systemd