board/minnowboard: grub.cfg: disable eudev network interface renaming

So the normal DHCP-on-eth0 logic works for the graphical defconfig where
eudev is used.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

board/minnowboard/grub.cfg

@@ -2,5 +2,5 @@ set default="0"
 set timeout="5"
 
 menuentry "Buildroot" {
-	linux /bzImage root=PARTLABEL=rootfs rootwait console=tty0 console=ttyS0,115200
+	linux /bzImage root=PARTLABEL=rootfs rootwait console=tty0 console=ttyS0,115200 net.ifnames=0
 }