bgmac: fix internal switch initialization

Some devices (BCM4749, BCM5357, BCM53572) have internal switch that
requires initialization. We already have code for this, but because
of the typo in code it was never working. This resulted in network not
working for some routers and possibility of soft-bricking them.

Use correct bit for switch initialization and fix typo in the define.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>