arm/dts: Add support for OMAP4 PandaBoard

Based on the original omap4-panda.dts file from Manju.
http://www.spinics.net/lists/linux-omap/msg55836.html



Add memory information and a default bootargs to allow
a boot from RAMDISK.

Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Cc: G, Manjunath Kondaiah <manjugk@ti.com>