netboot: Consistently use /dev/ram0 as the root when ramloading

/dev/ram is accepted by the kernel during boot, but there's no actual
file with this name in /dev, so RAUC will get confused about which
slot is actually one we booted from.

board/aarch64/rootfs/etc/rauc/system.conf

@@ -17,5 +17,5 @@ device=/dev/disk/by-partlabel/secondary
 bootname=secondary
 
 [slot.net.0]
-device=/dev/ram
+device=/dev/ram0
 bootname=net

board/common/qemu/qemu.sh

@@ -76,7 +76,7 @@ append_args()
     if [ "$CONFIG_QEMU_ROOTFS_INITRD" = "y" ]; then
 	# Size of initrd, rounded up to nearest kb
 	local size=$((($(stat -c %s $CONFIG_QEMU_ROOTFS) + 1023) >> 10))
-	echo -n "root=/dev/ram ramdisk_size=${size} "
+	echo -n "root=/dev/ram0 ramdisk_size=${size} "
     elif [ "$CONFIG_QEMU_ROOTFS_VSCSI" = "y" ]; then
 	echo -n "root=PARTLABEL=primary "
     fi

board/x86_64/grub.cfg

@@ -56,7 +56,7 @@ submenu "net" "$log"  {
 	set root=(initrd)
 
 	set slot="$1"
-	set append="console=ttyS0 root=/dev/ram ramdisk_size=65536 $2"
+	set append="console=ttyS0 root=/dev/ram0 ramdisk_size=65536 $2"
 	source /boot/grub/grub.cfg
     else
 	if [ -z "$net_efinet0_dhcp_next_server" ]; then

board/x86_64/rootfs/etc/rauc/system.conf

@@ -18,5 +18,5 @@ device=/dev/disk/by-partlabel/secondary
 bootname=secondary
 
 [slot.net.0]
-device=/dev/ram
+device=/dev/ram0
 bootname=net