ARM: dts: OMAP36xx: Add CPU OPP table

Add DT OPP table for OMAP36xx/37xx family of devices. This data is
decoded by OF with of_init_opp_table() helper function.

OPP data here is based on existing opp3xxx_data.c

This is in preparation to use generic cpufreq-cpu0 driver for device
tree enabled boot. Legacy non device tree enabled boot continues to
use omap-cpufreq.c and opp3xxx_data.c.

Signed-off-by: Nishanth Menon <nm@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Jon Hunter <jon-hunter@ti.com>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Keerthy <j-keerthy@ti.com>
Signed-off-by: Benoit Cousson <benoit.cousson@linaro.org>