spl: Add a parameter to spl_parse_image_header()

Instead of using the global spl_image variable, pass the required struct in
as an argument.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

common/spl/spl_ext.c

@@ -48,7 +48,7 @@ int spl_load_image_ext(struct blk_desc *block_dev,
 		goto end;
 	}
 
-	err = spl_parse_image_header(header);
+	err = spl_parse_image_header(&spl_image, header);
 	if (err < 0) {
 		puts("spl: ext: failed to parse image header\n");
 		goto end;