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>

common/board_r.c

@@ -484,7 +484,7 @@ static int initr_env(void)
 #endif
 
 	/* Initialize from environment */
-	load_addr = env_get_ulong("loadaddr", 16, load_addr);
+	image_load_addr = env_get_ulong("loadaddr", 16, image_load_addr);
 
 	return 0;
 }