tipc: make name table allocated dynamically

Name table locking policy is going to be adjusted from read-write
lock protection to RCU lock protection in the future commits. But
its essential precondition is to convert the allocation way of name
table from static to dynamic mode.

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