image: Fix script execution from FIT images with external data

Update the script loading code to recognize when script data is stored
externally from the FIT metadata (i.e., built with `mkimage -E`).

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

boot/image-board.c

@@ -1126,7 +1126,8 @@ fallback:
 			}
 
 			/* get script subimage data address and length */
-			if (fit_image_get_data(fit_hdr, noffset, &fit_data, &fit_len)) {
+			if (fit_image_get_data_and_size(fit_hdr, noffset,
+							&fit_data, &fit_len)) {
 				puts("Could not find script subimage data\n");
 				return 1;
 			}