synopsys/axs10x: Update /etc/inittab by post-build

To not maintain custom copy of inittab file lets adopt approach
used in raspberrypi adding post-build script for synopsys/axs10x
boards.

Signed-off-by: Evgeniy Didin <didin@synopsys.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: arc-buildroot@synopsys.com
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

board/synopsys/axs10x/fs-overlay/etc/inittab

@@ -1,42 +0,0 @@
-# /etc/inittab
-#
-# Copyright (C) 2001 Erik Andersen <andersen@codepoet.org>
-#
-# Note: BusyBox init doesn't support runlevels.  The runlevels field is
-# completely ignored by BusyBox init. If you want runlevels, use
-# sysvinit.
-#
-# Format for each entry: <id>:<runlevels>:<action>:<process>
-#
-# id        == tty to run on, or empty for /dev/console
-# runlevels == ignored
-# action    == one of sysinit, respawn, askfirst, wait, and once
-# process   == program to run
-
-# Startup the system
-::sysinit:/bin/mount -t proc proc /proc
-::sysinit:/bin/mount -o remount,rw /
-::sysinit:/bin/mkdir -p /dev/pts /dev/shm
-::sysinit:/bin/mount -a
-::sysinit:/sbin/swapon -a
-null::sysinit:/bin/ln -sf /proc/self/fd /dev/fd
-null::sysinit:/bin/ln -sf /proc/self/fd/0 /dev/stdin
-null::sysinit:/bin/ln -sf /proc/self/fd/1 /dev/stdout
-null::sysinit:/bin/ln -sf /proc/self/fd/2 /dev/stderr
-::sysinit:/bin/hostname -F /etc/hostname
-# now run any rc scripts
-::sysinit:/etc/init.d/rcS
-
-# /sbin/getty invocation for tty0
-tty0::respawn:/sbin/getty 115200 tty0
-
-# Put a getty on the serial port
-console::respawn:/sbin/getty -L console 0 vt100
-
-# Stuff to do for the 3-finger salute
-::ctrlaltdel:/sbin/reboot
-
-# Stuff to do before rebooting
-::shutdown:/etc/init.d/rcK
-::shutdown:/sbin/swapoff -a
-::shutdown:/bin/umount -a -r

board/synopsys/axs10x/post-build.sh

@@ -0,0 +1,11 @@
+#!/bin/sh
+
+set -u
+set -e
+
+# Add a console on tty0
+if [ -e ${TARGET_DIR}/etc/inittab ]; then
+    grep -qE '^tty0::' ${TARGET_DIR}/etc/inittab || \
+	sed -i '/GENERIC_SERIAL/a\
+tty0::respawn:/sbin/getty 115200  tty0' ${TARGET_DIR}/etc/inittab
+fi