br_stp_enable_bridge() does take the br->lock spinlock. Fix its wrongly
pasted comment and use the same as br_stp_disable_bridge().
Signed-off-by: NVivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>