classes: image-balena: provide board configuration hook

Add a hook for boards to initialize boot partition configuration.

Change-type: patch
Signed-off-by: Alex Gonzalez <alexg@balena.io>

meta-balena-common/classes/image-balena.bbclass

@@ -234,6 +234,7 @@ do_resin_boot_dirgen_and_deploy () {
     done
     echo "${IMAGE_NAME}" > ${BALENA_BOOT_WORKDIR}/image-version-info
     init_config_json ${BALENA_BOOT_WORKDIR}
+    command -v init_board_config > /dev/null && init_board_config
 
     # Keep this after everything is ready in the resin-boot directory
     find ${BALENA_BOOT_WORKDIR} -xdev -type f \