bridge: Refresh STP statistics separately from status
Currently, we refresh STP status (id, state, role) alongside
statistics (rx, tx, errors), all within instant_stats_run(). This
patch splits statistics out, and refreshes them with the 5 second
stats instead. This paves the way to reducing execution of
instant_stats_run().
Signed-off-by: Joe Stringer <joestringer@nicira.com> Signed-off-by: Ethan Jackson <ethan@nicira.com> Acked-by: Ethan Jackson <ethan@nicira.com>