ARM: dts: omap3-ldp: fix mmc configuration

MMC1 is the only MMC interface available on the platform. Further,
since the platform is based on older revision of SoC which is not
capable of doing multi-block reads, mark it with compatibility for the
same and add pinmux to ensure that all relevant pins are configured
for non-MMC boot mode.

Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Balaji T K <balajitk@ti.com>
Signed-off-by: Chris Ball <chris@printf.net>