net: sh-eth: Change read/write() param to struct sh_eth_info

This changes Change structure used in sh_eth_read and sh_eth_write function
from struct sh_eth_dev to struct sh_eth_info. This is necessary to convert
to Driver Model.

Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>