Treat an argument of "-" as meaning "read stdin for cpio files" so
gen_init_cpio can be piped into.
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>