tg3: Remove unused link config code

When tg3 devices are shutdown, the driver uses the
TG3_PHYFLG_IS_LOW_POWER flag to enable a static phy configuration.
Any attempt to use the link configuration variables is dead code.  This
patch removes such code.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>