ARM: dts: OMAP443x: Add CPU OPP table

Add DT OPP table for OMAP443x family of devices. This data is
decoded by OF with of_init_opp_table() helper function.

OPP data here is based on existing opp4xxx_data.c

Since the omap4460 OPP tables would be different from OMAP443x,
introduce an new omap443x.dtsi for 443x specific entries and use
existing omap4.dtsi as the common dtsi file for all OMAP4 platforms.

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 opp4xxx_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>