fit: Allow external data for FDTs

Switch to fit_image_get_data_and_size() for consistency with all other
data loaded from FIT.
Signed-off-by: NJohn Keeping <john@metanate.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>

common/image-fit.c

@@ -1777,7 +1777,8 @@ int fit_conf_find_compat(const void *fit, const void *fdt)
 			}
 
 			/* search in this config's kernel FDT */
-			if (fit_image_get_data(fit, kfdt_noffset, &fdt, &sz)) {
+			if (fit_image_get_data_and_size(fit, kfdt_noffset,
+							&fdt, &sz)) {
 				debug("Failed to get fdt \"%s\".\n", kfdt_name);
 				continue;
 			}