tipc: ensure all name sequences are properly protected with its lock

TIPC internally created a name table which is used to store name
sequences. Now there is a read-write lock - tipc_nametbl_lock to
protect the table, and each name sequence saved in the table is
protected with its private lock. When a name sequence is inserted
or removed to or from the table, its members might need to change.
Therefore, in normal case, the two locks must be held while TIPC
operates the table. However, there are still several places where
we only hold tipc_nametbl_lock without proprerly obtaining name
sequence lock, which might cause the corruption of name sequence.

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>