tipc: remove zeroing assignments to static global variables

Cleans up TIPC's source code to eliminate the needless initialization
of static variables to zero.

These changes are purely cosmetic and do not alter the operation of TIPC
in any way.

Signed-off-by: Allan Stephens <Allan.Stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>