fec: Add disable_giga parameter to force 10/100 operation

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
Revert "DT:imx6qdl: Pad SD2_DAT3 should have pull-down"

This reverts commit 5b15e9c5e96e25af6d278fdfbbbe0aac5fd04026.

The WL12xx driver doesn't like using this setting.
Merge remote-tracking branch 'upstream/boundary-imx_3.10.17_1.0.0_ga' into boundary-wand-imx_3.10.17_1.0.0_ga