net: sh_eth: add support for Renesas SuperH Ethernet

Add support for Renesas SuperH Ethernet controller.  This driver supports
SH7710 and SH7712.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>