spl: Rename spl_load_fit_image() to load_simple_fit()

We have two functions called spl_load_fit_image(), one in spl.c and one in
spl_fit.c

Rename the second one, to indicate that it relates to simple FIT parsing,
rather than the full version.

Signed-off-by: Simon Glass <sjg@chromium.org>
1 file changed