Revert "net/ucc_geth: Add SGMII support for UEC GETH driver"

This reverts commit 047584ce.

This patch meshes badly with "net: Rework ucc_geth driver to use
of_mdio infrastructure" (0b9da337).
Since most of the patch needs to be reworked, it is clearer to revert
the patch and then apply the corrected version

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>