fit: Fix CONFIG_FIT_SPL_PRINT

Rename CONFIG_FIT_SPL_PRINT to CONFIG_SPL_FIT_PRINT and add Kconfig
entry for it.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Simon Glass <sjg@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>