ARM: dts: omap3-gta04: Enable mmc2 for wifi

This requires vaux4.

Reset line isn't used yet, so wifi isn't reliable.
But it does work once per boot.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Marek Belisko <marek@goldelico.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>