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/net.c b/cmd/net.c
index 2374039..6bce214 100644
--- a/cmd/net.c
+++ b/cmd/net.c
@@ -186,10 +186,10 @@
 
 	net_boot_file_name_explicit = false;
 
-	/* pre-set load_addr */
+	/* pre-set image_load_addr */
 	s = env_get("loadaddr");
 	if (s != NULL)
-		load_addr = simple_strtoul(s, NULL, 16);
+		image_load_addr = simple_strtoul(s, NULL, 16);
 
 	switch (argc) {
 	case 1:
@@ -206,7 +206,7 @@
 		 */
 		addr = simple_strtoul(argv[1], &end, 16);
 		if (end == (argv[1] + strlen(argv[1]))) {
-			load_addr = addr;
+			image_load_addr = addr;
 			/* refresh bootfile name from env */
 			copy_filename(net_boot_file_name, env_get("bootfile"),
 				      sizeof(net_boot_file_name));
@@ -218,7 +218,7 @@
 		break;
 
 	case 3:
-		load_addr = simple_strtoul(argv[1], NULL, 16);
+		image_load_addr = simple_strtoul(argv[1], NULL, 16);
 		net_boot_file_name_explicit = true;
 		copy_filename(net_boot_file_name, argv[2],
 			      sizeof(net_boot_file_name));
@@ -227,8 +227,8 @@
 
 #ifdef CONFIG_CMD_TFTPPUT
 	case 4:
-		if (strict_strtoul(argv[1], 16, &save_addr) < 0 ||
-		    strict_strtoul(argv[2], 16, &save_size) < 0) {
+		if (strict_strtoul(argv[1], 16, &image_save_addr) < 0 ||
+		    strict_strtoul(argv[2], 16, &image_save_size) < 0) {
 			printf("Invalid address/size\n");
 			return CMD_RET_USAGE;
 		}