console-server: Fix leak of TTY sysfs dev node path

Identified by valgrind:

```
==1304== 50 bytes in 1 blocks are definitely lost in loss record 1 of 1
==1304==    at 0x4831C14: malloc (vg_replace_malloc.c:442)
==1304==    by 0x499D10F: strdup (strdup.c:42)
==1304==    by 0x4942913: realpath_stk (canonicalize.c:409)
==1304==    by 0x4942913: realpath@@GLIBC_2.4 (canonicalize.c:431)
==1304==    by 0x109CFF: UnknownInlinedFun (stdlib.h:42)
==1304==    by 0x109CFF: UnknownInlinedFun (console-server.c:143)
==1304==    by 0x109CFF: UnknownInlinedFun (console-server.c:359)
==1304==    by 0x109CFF: main (console-server.c:1000)
```

Change-Id: I614ef9f36d59587c6a633d679d0997136ab29bf3
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
diff --git a/console-server.c b/console-server.c
index 83f7e50..40c3288 100644
--- a/console-server.c
+++ b/console-server.c
@@ -174,6 +174,7 @@
 out_free:
 	free(tty_vuart_lpc_addr);
 	free(tty_class_device_link);
+	free(tty_sysfs_devnode);
 	free(tty_device_tty_dir);
 	free(tty_device_reldir);
 	free(tty_path_input);