SPL: Let spl_parse_image_header() return value

Allow the spl_parse_image_header() to return value. This is convenient
for controlling the SPL boot flow if the loaded image is corrupted.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Peng Fan <van.freenix@gmail.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Tom Rini <trini@konsulko.com>
diff --git a/common/spl/spl.c b/common/spl/spl.c
index 82e7f58..7259619 100644
--- a/common/spl/spl.c
+++ b/common/spl/spl.c
@@ -73,7 +73,7 @@
 	spl_image.name = "U-Boot";
 }
 
-void spl_parse_image_header(const struct image_header *header)
+int spl_parse_image_header(const struct image_header *header)
 {
 	u32 header_size = sizeof(struct image_header);
 
@@ -118,6 +118,7 @@
 		spl_set_header_raw_uboot();
 #endif
 	}
+	return 0;
 }
 
 __weak void __noreturn jump_to_image_no_args(struct spl_image_info *spl_image)