setup-disk with sys mode on Raspberry Pi 3.13.0

Commit "setup-disk: add rpi support" does not work on RPI.

Run command: setup-disk -m sys /mnt

Always get error Ext4 is not supported. Only supported are: VFAT"

Problem in source code :

     supported_boot_fs() {
	local supported="ext2 ext3 ext4 btrfs xfs vfat"
	local fs=
	**if is_rpi; then
		supported=vfat
	fi**
	for fs in $supported; do
		[ "$fs" = "$1" ] && return 0
	done

Fresh install with Alpine Linux 3.12.3 no problem