Support probing and init for 88E6071 switch.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Reviewed-by: Chris Packham <judge.packham@gmail.com>
Tested-by: Chris Packham <judge.packham@gmail.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>