omap5: emif: Add emif/ddr configurations required for omap5 evm

Add the emif configurations required for omap5 soc.Add the
correct ddr part configurations required for omap5 evm board.
EDB8164B3PH from ELPIDA is the part used on the board.

Also changes are done to retain some part of the code
common for OMAP4/5 and keep only the remaining in the Soc
specific directories.

Signed-off-by: sricharan <r.sricharan@ti.com>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>