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/bootz.c b/cmd/bootz.c
index 74be62c..7bfc491 100644
--- a/cmd/bootz.c
+++ b/cmd/bootz.c
@@ -33,9 +33,9 @@
 
 	/* Setup Linux kernel zImage entry point */
 	if (!argc) {
-		images->ep = load_addr;
+		images->ep = image_load_addr;
 		debug("*  kernel: default image load address = 0x%08lx\n",
-				load_addr);
+				image_load_addr);
 	} else {
 		images->ep = simple_strtoul(argv[0], NULL, 16);
 		debug("*  kernel: cmdline image address = 0x%08lx\n",