Converts a non-trivial routine from inline to non-inline form
to avoid bloating the TIPC code base with 6 copies of its body.

This change is essentially cosmetic, and doesn't change existing
TIPC behavior.
Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>