net: sh_eth: modify a condition of ioremap for TSU

If the controller has TSU, the each channel needs TSU registers.
This patch also fixes the iounmap condition in the sh_eth_drv_remove().

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>