Revert "bridge: Forward reserved group addresses if !STP"

This reverts commit 1e253c3b.

It breaks 802.3ad bonding inside of a bridge.

The commit was meant to support transport bridging, and specifically
virtual machines bridged to an ethernet interface connected to a
switch port wiht 802.1x enabled.

But this isn't the way to do it, it breaks too many other things.

Signed-off-by: David S. Miller <davem@davemloft.net>