tcp: Make reuse crit section wider

This lock will have to be moved into the libsocr which is
not nice, so pull this out of the restore_tcp_queues.

And, since we're extending the section anyway, pull it away
from sk-tcp.c at all. Makes the code a little bit cleaner.

Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>