ARM: imx: add enet init for i.mx6sx
ARM: imx: add enet init for i.mx6sx

Add enet init for i.mx6sx:
- Add phy ar8031 fixup
- Set enet clock source from internal PLL

Signed-off-by: Fugang Duan <9b59a7962753ebf931b546cc568d1169b235ae3e@freescale.com>
Signed-off-by: Shawn Guo <912cf7eb7d8018e2943586ae6657d21fd4e38239@freescale.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs