sh: convert magicpanelr2 platform to use smsc911x.

Signed-off-by: Steve Glendinning <steve.glendinning@smsc.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>