tipc: bump max configurable window size

The maximum window size is limited by the sequence gap field, which
was expanded with bd784533
("tipc: Expand link sequence gap field to 13 bits")
We remove the artificial limit that prevents the link window to be
set larger than 150.

Signed-off-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>