devfs and tty layer.

[James Simmons]

Hi!

   As you already seen there has been a issue with devfs and the VT code.
I have moved the tty registeration later for VTs so the TTY_DRIVER_NO_DEVFS
flag was no longer needed. Because I removed this now tty_register_driver
calls tty_register_devfs instead of con_init_devfs. Now when con_init_devfs
was calling tty_register_devfs it was passing a different flag to devfs
then the default tty_register_driver does. So I have been thinking about
different approachs to the problem.

1) The first approach is to change the tty_register_devfs function to pass
   in the flag.

2) Add a devfs flag field to struct tty_driver.

3) Remove tty_register_devfs from tty_register_driver and have each tty
   driver call tty_register_devfs its self.

What solution would you do?