configs/minnowboard_max-graphical: don't use custom post-image script

Use support/scripts/genimage.sh, instead, which prevents duplicating
TARGET_DIR under ${BUILD_DIR}/genimage.tmp/root.

Signed-off-by: Carlos Santos <unixmania@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

configs/minnowboard_max-graphical_defconfig

@@ -13,7 +13,8 @@ BR2_TOOLCHAIN_BUILDROOT_WCHAR=y
 BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_EUDEV=y
 BR2_ROOTFS_OVERLAY="board/minnowboard/fs-overlay-graphical"
 BR2_ROOTFS_POST_BUILD_SCRIPT="board/minnowboard/post-build.sh"
-BR2_ROOTFS_POST_IMAGE_SCRIPT="board/minnowboard/post-image.sh"
+BR2_ROOTFS_POST_IMAGE_SCRIPT="support/scripts/genimage.sh"
+BR2_ROOTFS_POST_SCRIPT_ARGS="-c board/minnowboard/genimage.cfg"
 
 # Host packages
 BR2_PACKAGE_HOST_DOSFSTOOLS=y