fs/cpio/init: preserve arguments

Use "$@" instead of $* to preserve arguments containing spaces.

The shell expands "$@" as "$1" "$2" "$3"... while it expands $@ as $1 $2
$3. With the second form, we loses spaces in positional parameters.

Signed-off-by: Gaël PORTAY <gael.portay@savoirfairelinux.com>
Reviewed-by: Adrian Perez de Castro <aperez@igalia.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>