MLK-12623-01 cpufreq: imx: Add support for 700MHz setpoint in cpufreq

MLK-12623-01 cpufreq: imx: Add support for 700MHz setpoint in cpufreq

On i.MX6UL EVK board, we use a external GPIO DC regulator to control
the VDD_ARM_SOC_IN voltage, if default voltage is 1.4V when the system
is bootup. Per design team, when the highest setpoint freq is not
bigger than 528MHz, we can decrease this regulator voltage to 1.3V.
On i.MX6UL TO1.1, we add a 700MHz setpoint. When the highest setpoint
freq is 700MHz, the DC regulator should be at 1.4V to to cover the IR
drop.

Signed-off-by: Bai Ping <ping.bai@nxp.com>