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/fit_image.c b/tools/fit_image.c
index 0400a60..1466164 100644
--- a/tools/fit_image.c
+++ b/tools/fit_image.c
@@ -14,6 +14,7 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 
+#include "imagetool.h"
 #include "mkimage.h"
 #include <image.h>
 #include <u-boot/crc.h>
@@ -21,7 +22,7 @@
 static image_header_t header;
 
 static int fit_verify_header (unsigned char *ptr, int image_size,
-			struct mkimage_params *params)
+			struct image_tool_params *params)
 {
 	return fdt_check_header(ptr);
 }
@@ -34,7 +35,7 @@
 		return EXIT_FAILURE;
 }
 
-int mmap_fdt(struct mkimage_params *params, const char *fname, void **blobp,
+int mmap_fdt(struct image_tool_params *params, const char *fname, void **blobp,
 		struct stat *sbuf)
 {
 	void *ptr;
@@ -88,7 +89,7 @@
  * returns:
  *     only on success, otherwise calls exit (EXIT_FAILURE);
  */
-static int fit_handle_file (struct mkimage_params *params)
+static int fit_handle_file(struct image_tool_params *params)
 {
 	char tmpfile[MKIMAGE_MAX_TMPFILE_LEN];
 	char cmd[MKIMAGE_MAX_DTC_CMDLINE_LEN];
@@ -184,7 +185,7 @@
 	return -1;
 }
 
-static int fit_check_params (struct mkimage_params *params)
+static int fit_check_params(struct image_tool_params *params)
 {
 	return	((params->dflag && (params->fflag || params->lflag)) ||
 		(params->fflag && (params->dflag || params->lflag)) ||
@@ -205,5 +206,5 @@
 
 void init_fit_image_type (void)
 {
-	mkimage_register (&fitimage_params);
+	register_image_type(&fitimage_params);
 }