[PATCH] drivers: tty: vt: vt.c: fix NULL dereference crash

[Du Cheng]

Hi Fatih,
I just found out that the section [Patch testing requests] on
https://syzkaller.appspot.com/bug?id=defb47bf56e1c14d5687280c7bb91ce7b608b94b,
indicates that you did not attach the patch when sending email to syzbot. syzbot
was simply testing the vallina upstream with repro.c, so it failed as expected.

Anyway, I resent the test email *with the patch* from Hassan to syzbot, and
let's see the result.

Regards,
Du Cheng