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/common/image.c b/common/image.c
index e8ecfa5..d0f169d 100644
--- a/common/image.c
+++ b/common/image.c
@@ -139,6 +139,7 @@
 	{	IH_TYPE_SCRIPT,     "script",	  "Script",		},
 	{	IH_TYPE_STANDALONE, "standalone", "Standalone Program", },
 	{	IH_TYPE_FLATDT,     "flat_dt",    "Flat Device Tree",	},
+	{	IH_TYPE_KWBIMAGE,   "kwbimage",   "Kirkwood Boot Image",},
 	{	-1,		    "",		  "",			},
 };