bridge: minor cleanups

Some minor cleanups that won't impact code:
  1. Remove inline from non-critical functions; compiler will most
     likely inline them anyway.
  2. Make function args const where possible.
  3. Whitespace cleanup

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>