[new uImage] Correct raw FDT blob handlig when CONFIG_FIT is disabled

Dual format image code must properly handle all three FDT passing methods:
- raw FDT blob passed
- FDT blob embedded in the legacy uImage
- FDT blob embedded in the new uImage

This patch enables proper raw FDT handling when no FIT imaeg support
is compiled in. This is a bit tricky as we must dected FIT format even
when FIT uImage handling is not enabled as both FIT uImages and raw FDT
blobs use tha same low level format (libfdt).

Signed-off-by: Marian Balakowicz <m8@semihalf.com>

common/image.c

@@ -375,6 +375,10 @@ void image_print_contents (image_header_t *hdr)
  * gen_image_get_format() checks whether provided address points to a valid
  * legacy or FIT image.
  *
+ * New uImage format and FDT blob are based on a libfdt. FDT blob
+ * may be passed directly or embedded in a FIT image. In both situations
+ * gen_image_get_format() must be able to dectect libfdt header.
+ *
  * returns:
  *     image format type or IMAGE_FORMAT_INVALID if no image is present
  */
@@ -382,14 +386,14 @@ int gen_image_get_format (void *img_addr)
 {
 	ulong		format = IMAGE_FORMAT_INVALID;
 	image_header_t	*hdr;
-#if defined(CONFIG_FIT)
+#if defined(CONFIG_FIT) || defined(CONFIG_OF_LIBFDT)
 	char		*fit_hdr;
 #endif
 
 	hdr = (image_header_t *)img_addr;
 	if (image_check_magic(hdr))
 		format = IMAGE_FORMAT_LEGACY;
-#if defined(CONFIG_FIT)
+#if defined(CONFIG_FIT) || defined(CONFIG_OF_LIBFDT)
 	else {
 		fit_hdr = (char *)img_addr;
 		if (fdt_check_header (fit_hdr) == 0)