[BRIDGE]: eliminate workqueue for carrier check

Having a work queue for checking carrier leads to lots of race issues.
Simpler to just get the cost when data structure is created and
update on change.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc net/bridge/br_if.c
Simple merge

diff --cc net/bridge/br_notify.c
Simple merge

diff --cc net/bridge/br_private.h
Simple merge