This driver is used for MDIO muxes driven over I2C.  This is currently
used on Freescale LS1028A QDS board, on which the physical MDIO MUX is
controlled by an on-board FPGA which in turn is configured through I2C.
Signed-off-by: NAlex Marginean <alexm.osslist@gmail.com>
Acked-by: NJoe Hershberger <joe.hershberger@ni.com>
Reviewed-by: NBin Meng <bmeng.cn@gmail.com>