Add OPP data for OMAP34xx and OMAP36xx and initialization functions
to populate OPP tables based on current SoC.
introduce an OMAP generic opp initialization routine which OMAP3
and OMAP4+ SoCs can use to register their OPP definitions.

Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>