image: Rename load_addr, save_addr, save_size

These global variables are quite short and generic. In fact the same name
is more often used locally for struct members and function arguments.

Add a image_ prefix to make them easier to distinguish.

Signed-off-by: Simon Glass <sjg@chromium.org>

cmd/disk.c

@@ -124,7 +124,7 @@ int common_diskboot(cmd_tbl_t *cmdtp, const char *intf, int argc,
 	flush_cache(addr, (cnt+1)*info.blksz);
 
 	/* Loading ok, update default load address */
-	load_addr = addr;
+	image_load_addr = addr;
 
 	return bootm_maybe_autostart(cmdtp, argv[0]);
 }