sh_eth: make sh_eth_tsu_{read|write}_entry() prototypes symmetric

sh_eth_tsu_read_entry() is still asymmetric with sh_eth_tsu_write_entry()
WRT their prototypes -- make them symmetric by passing to the former a TSU
register offset instead of its address and also adding the (now necessary)
'ndev' parameter...

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>