mkimage: ublimage must return if the header is not verified

Each image handler must return a not-zero velue if the
header is not recognized to allow the main program to
iterate to the next handler.

Signed-off-by: Stefano Babic <sbabic@denx.de>
CC: Heiko Schocher <hs@denx.de>
Acked-by: Heiko Schocher <hs@denx.de>

tools/ublimage.c

@@ -214,6 +214,11 @@ static int ublimage_check_image_types(uint8_t type)
 static int ublimage_verify_header(unsigned char *ptr, int image_size,
 			struct mkimage_params *params)
 {
+	struct ubl_header *ubl_hdr = (struct ubl_header *)ptr;
+
+	if ((ubl_hdr->magic & 0xFFFFFF00) != UBL_MAGIC_BASE)
+		return -1;
+
 	return 0;
 }