Now that we have converted the bridge code and the drivers to check for
bridge port(s) flags at the time we try to set them, there is no need
for a get() -> set() sequence anymore and
SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS_SUPPORT therefore becomes unused.

Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>