[PATCH] tty: lock ticogwinsz

Now we lock the set ioctl its trivial to lock the get one so the data
copied is consistent.  At the moment we have the BKL here but this removes
the need for it and is a step in the right direction

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>