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>
diff --git a/configs/snps_arc700_axs101_defconfig b/configs/snps_arc700_axs101_defconfig
index 2a71ff3..4f796b4 100644
--- a/configs/snps_arc700_axs101_defconfig
+++ b/configs/snps_arc700_axs101_defconfig
@@ -6,7 +6,7 @@
 BR2_TARGET_GENERIC_ISSUE="Welcome to the ARC Software Development Platform"
 BR2_TARGET_ROOTFS_INITRAMFS=y
 BR2_SYSTEM_DHCP="eth0"
-BR2_ROOTFS_OVERLAY="board/synopsys/axs10x/fs-overlay"
+BR2_ROOTFS_POST_BUILD_SCRIPT="board/synopsys/axs10x/post-build.sh"
 
 # Linux headers same as kernel, a 4.16 series
 BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_16=y
diff --git a/configs/snps_archs38_axs103_defconfig b/configs/snps_archs38_axs103_defconfig
index 1ad79eb..456d4cb 100644
--- a/configs/snps_archs38_axs103_defconfig
+++ b/configs/snps_archs38_axs103_defconfig
@@ -7,7 +7,7 @@
 BR2_TARGET_GENERIC_ISSUE="Welcome to the ARC Software Development Platform"
 BR2_TARGET_ROOTFS_INITRAMFS=y
 BR2_SYSTEM_DHCP="eth0"
-BR2_ROOTFS_OVERLAY="board/synopsys/axs10x/fs-overlay"
+BR2_ROOTFS_POST_BUILD_SCRIPT="board/synopsys/axs10x/post-build.sh"
 
 # Linux headers same as kernel, a 4.16 series
 BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_16=y