omap5: clocks: Add clocks support for omap5 platform.

Adding the correct configurations required for
dplls, clocks, for omap5 Soc.

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

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