server: enable file is no longer exposed by recent VUART drivers

... as the enable status is set automatically now. Remove the code to
set the sysfs attribute.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
diff --git a/console-server.c b/console-server.c
index 3857de1..9677064 100644
--- a/console-server.c
+++ b/console-server.c
@@ -168,7 +168,6 @@
 	if (console->tty_lpc_addr)
 		tty_set_sysfs_attr(console, "lpc_address",
 				console->tty_lpc_addr);
-	tty_set_sysfs_attr(console, "enabled", 1);
 
 	console->tty_fd = open(console->tty_dev, O_RDWR);
 	if (console->tty_fd <= 0) {