ARM: dts: omap3-igep0020: use SMSC9221 timings

The IGEPv2 board has a SMSC LAN9221i ethernet chip and not a
SMSC LAN911x connected to the GPMC. Each chip needs different
timings in order to operate correctly so is wrong to include
omap-gpmc-smsc911x.dtsi instead of omap-gpmc-smsc9221.dtsi.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
[tony@atomide.com: this is needed to avoid potential memory corruption]
Signed-off-by: Tony Lindgren <tony@atomide.com>