Initialize device numbers for newly allocated ptys. Prevents a panic caused by

Initialize device numbers for newly allocated ptys. Prevents a panic caused by
the following: a new pty is allocated in which the kernel console output is
redirected to, poll(2):ing from /dev/console at this point would be delegated to
the device with the major number taken from the pty due to the earlier
redirection. Since the pty does not have its correct device major assigned, the
wrong device ends up being used.

ok deraadt@ millert@