mkimage: Add Kirkwood Boot Image support (kwbimage)

This patch adds support for "kwbimage" (Kirkwood Boot Image)
image types to the mkimage code.

For details refer to docs/README.kwbimage

This patch is tested with Sheevaplug board

Signed-off-by: Prafulla Wadaskar <prafulla@marvell.com>
Acked-by: Ron Lee <ron@debian.org>

Signed-off-by: Prafulla Wadaskar <prafulla@marvell.com>
diff --git a/include/image.h b/include/image.h
index d4cbf8c..5a424e6 100644
--- a/include/image.h
+++ b/include/image.h
@@ -155,6 +155,7 @@
 #define IH_TYPE_SCRIPT		6	/* Script file			*/
 #define IH_TYPE_FILESYSTEM	7	/* Filesystem Image (any type)	*/
 #define IH_TYPE_FLATDT		8	/* Binary Flat Device Tree Blob	*/
+#define IH_TYPE_KWBIMAGE	9	/* Kirkwood Boot Image		*/
 
 /*
  * Compression Types