net: cosmetic: Fixup var names related to boot file

The variables around the bootfile were inconsistent and used CamelCase.
Update them to make the code more readable.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/common/update.c b/common/update.c
index cc830a7..bc0c48f 100644
--- a/common/update.c
+++ b/common/update.c
@@ -58,7 +58,7 @@
 	saved_timeout_msecs = TftpRRQTimeoutMSecs;
 	saved_timeout_count = TftpRRQTimeoutCountMax;
 	saved_netretry = strdup(getenv("netretry"));
-	saved_bootfile = strdup(BootFile);
+	saved_bootfile = strdup(net_boot_file_name);
 
 	/* set timeouts for auto-update */
 	TftpRRQTimeoutMSecs = msec_max;
@@ -69,7 +69,7 @@
 
 	/* download the update file */
 	load_addr = addr;
-	copy_filename(BootFile, filename, sizeof(BootFile));
+	copy_filename(net_boot_file_name, filename, sizeof(net_boot_file_name));
 	size = NetLoop(TFTPGET);
 
 	if (size < 0)
@@ -86,7 +86,8 @@
 		free(saved_netretry);
 
 	if (saved_bootfile != NULL) {
-		copy_filename(BootFile, saved_bootfile, sizeof(BootFile));
+		copy_filename(net_boot_file_name, saved_bootfile,
+			      sizeof(net_boot_file_name));
 		free(saved_bootfile);
 	}