arm/dts: omap5: Add mmc controller nodes and board data

Add OMAP MMC related device tree data for OMAP5.

Signed-off-by: Balaji T K <balajitk@ti.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Tony Lindgren <tony@atomide.com>