ARM: dts: vf610-zii-scu4-aib: Configure fibre ports to 1000BaseX

The SFF soldered onto the board expect the ports to use 1000BaseX.  It
makes no sense to have the ports set to SGMII, since they don't even
support that mode.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Chris Healy <cphealy@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>