tools: moved code common to all image tools to a separated module.

In order to avoid duplicating code and keep only one point of modification,
the functions, structs and defines useful for "dumpimage" were moved from
"mkimage" to a common module called "imagetool".

This modification also weakens the coupling between image types (FIT, IMX, MXS,
and so on) and image tools (mkimage and dumpimage). Any tool may initialize the
"imagetool" through register_image_tool() function, while the image types
register themselves within an image tool using the register_image_type()
function:

                                                      +---------------+
                                               +------|   fit_image   |
 +--------------+          +-----------+       |      +---------------+
 |    mkimage   |--------> |           | <-----+
 +--------------+          |           |              +---------------+
                           | imagetool | <------------|    imximage   |
 +--------------+          |           |              +---------------+
 |  dumpimage   |--------> |           | <-----+
 +--------------+          +-----------+       |      +---------------+
                                               +------| default_image |
                                                      +---------------+

          register_image_tool()           register_image_type()

Also, the struct "mkimage_params" was renamed to "image_tool_params" to make
clear its general purpose.

Signed-off-by: Guilherme Maciel Ferreira <guilherme.maciel.ferreira@gmail.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/mxsimage.c b/tools/mxsimage.c
index 5db19b2..b214050 100644
--- a/tools/mxsimage.c
+++ b/tools/mxsimage.c
@@ -17,7 +17,7 @@
 
 #include <openssl/evp.h>
 
-#include "mkimage.h"
+#include "imagetool.h"
 #include "mxsimage.h"
 #include <image.h>
 
@@ -2148,11 +2148,11 @@
 }
 
 static void mxsimage_set_header(void *ptr, struct stat *sbuf, int ifd,
-				struct mkimage_params *params)
+				struct image_tool_params *params)
 {
 }
 
-int mxsimage_check_params(struct mkimage_params *params)
+int mxsimage_check_params(struct image_tool_params *params)
 {
 	if (!params)
 		return -1;
@@ -2193,7 +2193,7 @@
 
 char *imagefile;
 static int mxsimage_verify_header(unsigned char *ptr, int image_size,
-			struct mkimage_params *params)
+			struct image_tool_params *params)
 {
 	struct sb_boot_image_header *hdr;
 
@@ -2291,7 +2291,7 @@
 	return 0;
 }
 
-static int mxsimage_generate(struct mkimage_params *params,
+static int mxsimage_generate(struct image_tool_params *params,
 	struct image_type_params *tparams)
 {
 	int ret;
@@ -2337,7 +2337,7 @@
 
 void init_mxs_image_type(void)
 {
-	mkimage_register(&mxsimage_params);
+	register_image_type(&mxsimage_params);
 }
 
 #else