net: ethernet: freescale: set FEC ethtool regs version

Currently the ethtool_regs version is set to 0 for FEC devices.

Use this field to store the register dump version exposed by the
kernel. The choosen version 2 corresponds to the kernel compile test:

        #if defined(CONFIG_M523x) || defined(CONFIG_M527x)
        || defined(CONFIG_M528x) || defined(CONFIG_M520x)
        || defined(CONFIG_M532x) || defined(CONFIG_ARM)
        || defined(CONFIG_ARM64) || defined(CONFIG_COMPILE_TEST)

and version 1 corresponds to the opposite. Binaries of ethtool unaware
of this version will dump the whole set as usual.

Signed-off-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>