tty/vt: prevent registration of console with invalid number

If a user specifies an invalid console like 'console=tty3000',
the vt driver should prevent setting up a vt entry for that.

Suggested-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Link: https://lore.kernel.org/r/20221209112737.3222509-3-svens@linux.ibm.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>