SH7619: fix typo in Ether platform data

Commit 06a64f91 (SH7619: fix Ether support)  has
a typo in the 'phy_interface' field name of the platform data which causes build
error -- fix it.

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