tsec: Revert to setting TBICR_ANEG_ENABLE by default for SGMII

The following commit:

commit 46e91674
Author: Peter Tyser <ptyser@xes-inc.com>
Date:   Tue Nov 3 17:52:07 2009 -0600

    tsec: Force TBI PHY to 1000Mbps full duplex in SGMII mode

Removed setting Auto-Neg by default, however this is believed to be
proper default configuration for initialization of the TBI interface.

Instead we explicitly set CONFIG_TSEC_TBICR_SETTINGS for the
XPedite5370 & XPedite5500 boards that use a Broadcomm PHY which require
Auto-Neg to be disabled to function properly.

This addresses a breakage on the P2020 DS & MPC8572 DS boards when used
with an SGMII riser card.  We also remove setting
CONFIG_TSEC_TBICR_SETTINGS on the P1_P2_RDB family of boards as now the
default setting is sufficient for them.

Additionally, we clean up the code a bit to remove an unnecessary second
define.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Peter Tyser <ptyser@xes-inc.com>
Tested-by: Peter Tyser <ptyser@xes-inc.com>