net: sgi: ioc3-eth: Remove phy workaround

Commit a8d0f11e ("MIPS: SGI-IP27: Enable ethernet phy on second
Origin 200 module") fixes the root cause of not detected PHYs.
Therefore the workaround can go away now.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: David S. Miller <davem@davemloft.net>