boot: Rename fit_image_get_data()

This function can only be used with FITs that use embedded data. Rename
it so this is clear.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/common/spl/spl_fit.c b/common/spl/spl_fit.c
index ac84625..64c4349 100644
--- a/common/spl/spl_fit.c
+++ b/common/spl/spl_fit.c
@@ -289,7 +289,7 @@
 		src = src_ptr + overhead;
 	} else {
 		/* Embedded data */
-		if (fit_image_get_data(fit, node, &data, &length)) {
+		if (fit_image_get_emb_data(fit, node, &data, &length)) {
 			puts("Cannot get image data/size\n");
 			return -ENOENT;
 		}