ARM: dts: am335x: Update MPU regulator range for TI boards

Now that we are moving to OPPv2 bindings and able to add 1GHz OPP for
MPU, let's update the max MPU voltage range to align with the maximum
possible value allowed in the operating-points table, which is max
target voltage of 132500 uV + 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>