arm/dts: remove MMC/SD and SPI related entries from am33xx.dtsi

arm/dts: remove MMC/SD and SPI related entries from am33xx.dtsi

The MMC/SD and SPI entries in this file are not tested yet. They
inadvertently came into the patch because of some work in progress
stuff I had in my repo.

These entries should not have been sent out in the first place and
I am sorry for the trouble and will be extra careful in future.

Since the offending commit is not sent upstream yet, I hope this can
be merged into the commit 5fc0b42a98556bd9f01cecc6a64fcbd15ec363f0
(arm/dts: Add initial DT support for AM33XX SoC family) on the devel-dt
branch of linux-omap tree.

Signed-off-by: AnilKumar Ch <anilkumar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>