busybox: Fix busybox-init on non-tty consoles

When using non-tty consoles (e.g. VirtIO console /dev/hvc0) the
current init system fails with:
process '/sbin/getty 115200 hvc0' (pid 545) exited. Scheduling for restart.
can't open /dev/ttyhvc0: No such file or directory

The first field needs to be a valid device. The BusyBox inittab example
explains as follows:
"<id>: WARNING: This field has a non-traditional meaning for BusyBox init!

The id field is used by BusyBox init to specify the controlling tty for
the specified process to run on.  The contents of this field are
appended to "/dev/" and used as-is."

(From OE-Core rev: a53393082f331a613cb3eb973a07bab22cefcde8)

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/busybox/busybox.inc

@@ -286,8 +286,8 @@ do_install () {
                         for i in $tmp
                         do
                                 j=`echo ${i} | sed s/\;/\ /g`
-                                label=`echo ${i} | sed -e 's/tty//' -e 's/^.*;//' -e 's/;.*//'`
-                                echo "tty$label::respawn:${base_sbindir}/getty ${j}" >> ${D}${sysconfdir}/inittab
+                                id=`echo ${i} | sed -e 's/^.*;//' -e 's/;.*//'`
+                                echo "$id::respawn:${base_sbindir}/getty ${j}" >> ${D}${sysconfdir}/inittab
                         done
                 fi
         fi