TTY: con3215, centralize allocation

There are two copies of allocations of device information. One of them
is totally broken. See:
raw->cdev = cdev;
raw->inbuf = (char *) raw + sizeof(struct raw3215_info);
memset(raw, 0, sizeof(struct raw3215_info));

It suggests that this path was never executed. The code uses both
raw->cdev and raw->inbuf all over. And it is NULL due to the memset
here, so it would panic immediately. I believe nobody used that driver
without being a system console.

Either way, let us fix it by moving the allocations (and
initializations) to a single place. This will save us some double
initializations later too.

And while at it, initialize the timer properly -- once, at the
allocation.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>