Revert "tools: fit_image: Add the loadable property to configs"

This is not correct when building a kernel FIT, since it adds a second
loadable in addition to the kernel.

There may in fact be a bug in SPL FIT, in which case that should be
fixed, rather than adding an invalid loadable to the FIT.

This reverts commit cabde449b9.

Series-to: concept
Series-cc: heinrich
Cover-letter:
mkimage: Start to tidy up mkimage and friends
The current mkimage code is a bit messy:

- the main() function is very long
- two similarly named structs are used throughout: the first
  (struct image_tool_params) is not actually just parameters, the second
  (struct image_type_params) is confusingly similar
- quite a bit of FIT processing happens right at the start of main(),
  which can be hard to follow
- the program calls exit() from many different places

This series renames the main structures, avoiding using the common
'params' word. It breaks up part of main() into separate functions and
starts the process of exiting in one place.

It also reverts a patch which causes an invalid 'loadables' property to
be added with '-f auto'.

More remains to be done, but this is a start.
END

tools/fit_image.c

@@ -381,7 +381,6 @@ static void fit_write_configs(struct imgtool *itl, char *fdt)
 		typename = genimg_get_type_short_name(itl->fit_image_type);
 		snprintf(str, sizeof(str), "%s-1", typename);
 		fdt_property_string(fdt, typename, str);
-		fdt_property_string(fdt, FIT_LOADABLE_PROP, str);
 
 		if (itl->fit_ramdisk)
 			fdt_property_string(fdt, FIT_RAMDISK_PROP,