imx6: kernel: add GW16083 Ethernet Expansion Mezzanine support

The GW16083 Ethernet Expansion Mezzanine adds the following to supported
Gateworks baseboards:
 * 7-port Ethernet Switch
  * 4x RJ45 ports (ENET1-4) supporing 802.11af/at PoE (with optional PoE module)
  * 2x RJ45 ports or SFP module (ENET5-6) (auto-selected)

This series adds support for a phy driver that adds support for ENET5/ENET6
PHY adding initialization for those PHY's and a polling mechanism that detects
SFP insertion and configuration.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>

SVN-Revision: 42147