lantiq: support loading the dsl firmware from a flash partition as a raw gzipped tarfile

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@40715 3c298f89-4303-0410-b956-a3cf2f4a3e73
ltq-vdsl-fw: vdsl_fw_install.sh: store firmware as tar.gz in flash

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@40716 3c298f89-4303-0410-b956-a3cf2f4a3e73