Makefile: Drop SPL_FIT_GENERATOR support

The SPL_FIT_GENERATOR is long superseded by binman, drop SPL_FIT_GENERATOR
support as there are no more users.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/22109373594b6a5d1110be9420ccd8fbb93a61d3.1730452668.git.michal.simek@amd.com
3 files changed