net: sh_eth: add value of ether_link pin in platform_data

The method of ETHER_LINK pin is board dependence.
This patch adding paramters are:
 - no_ether_link          : If set to 1, do not use ETHER_LINK
 - ether_link_active_low  : If set to 1, ETHER_LINK is active low.

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