PROD_IMAGE is a flag that indicates a production image should be
built, and will be set for dev builds if the user specifies that
both dev and prod images should be built. build_image was
incorrectly using the PROD_IMAGE variable to conditionaly do some
setup depending on the image type.
Add a new variable IMAGE_BUILD_TYPE that can be tested for the type
of image currently being built and replace the PROD_IMAGE usage.
Signed-off-by: Geoff Levand <geoff@infradead.org>
c053521e37