ARM: dts: am4372: Add operating-points-v2 table

Add an operating-points-v2 table with all OPPs available for all silicon
revisions along with necessary data for use by ti-cpufreq to selectively
enable the appropriate OPPs at runtime.

Information from AM437x Data Manual, SPRS851B, Revised April 2015,
Table 5-2.

Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>