Linksys devices do no pass $cmd at all.
Fixes: #16148
Fixes: 715634e6d1 ("base-files: upgrade: nand: use "cmd" argument for extracting command")
Signed-off-by: Boris Krasnovskiy <borkra@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/16690
Signed-off-by: Robert Marko <robimarko@gmail.com>