tools/fit_image.c: Update some return code paths

Coverity has found some problems with the return paths in parts of this
code.  We have a case where we were going to the wrong part of the
unwind (open() failed so we cannot close the fd), a case where we were
only free()ing our buf on the error path and finally a case where we did
not munmap in the failure path.

Reported-by: Coverity (CID: 138492, 138495, 143064)
Signed-off-by: Tom Rini <trini@konsulko.com>

tools/fit_image.c

@@ -372,7 +372,7 @@ static int fit_build(struct image_tool_params *params, const char *fname)
 	if (fd < 0) {
 		fprintf(stderr, "%s: Can't open %s: %s\n",
 			params->cmdname, fname, strerror(errno));
-		goto err;
+		goto err_buf;
 	}
 	ret = write(fd, buf, size);
 	if (ret != size) {
@@ -501,6 +501,7 @@ static int fit_extract_data(struct image_tool_params *params, const char *fname)
 		ret = -EIO;
 		goto err;
 	}
+	free(buf);
 	close(fd);
 	return 0;
 
@@ -601,6 +602,7 @@ static int fit_import_data(struct image_tool_params *params, const char *fname)
 	ret = 0;
 
 err:
+	munmap(old_fdt, sbuf.st_size);
 	free(fdt);
 	close(fd);
 	return ret;