tipc: Optimize initialization of network topology service

Initialization now occurs in the calling thread of control,
rather than being deferred to the TIPC tasklet.  With the
current codebase, the deferral is no longer necessary.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>