ARM: dts: omap5: Update CPU OPP table as per final production Manual

ARM: dts: omap5: Update CPU OPP table as per final production Manual

As per the Final production Data Manual for OMAP5432,
SWPS050F(APRIL 2014)

There are only two OPPs - 1GHz and 1.5GHz. the older OPP_LOW has been
completely descoped. The Nominal voltages are still correct though.
However, expectation for final production configuration is operation
with Adaptive Body Bias (ABB) and Adaptive Voltage Scaling Class 0
operation.

There are no IDcode or version change information encoded to
programmatically detect this and software is supposed to NOT use
OPP_LOW(500MHz) anymore for all devices (legacy and production
samples).

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>