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>
diff --git a/cmd/source.c b/cmd/source.c
index 3a51ebf..be11350 100644
--- a/cmd/source.c
+++ b/cmd/source.c
@@ -172,7 +172,8 @@
 		addr = CONFIG_SYS_LOAD_ADDR;
 		debug ("*  source: default load address = 0x%08lx\n", addr);
 #if defined(CONFIG_FIT)
-	} else if (fit_parse_subimage (argv[1], load_addr, &addr, &fit_uname)) {
+	} else if (fit_parse_subimage(argv[1], image_load_addr, &addr,
+				      &fit_uname)) {
 		debug ("*  source: subimage '%s' from FIT image at 0x%08lx\n",
 				fit_uname, addr);
 #endif