cpufreq: mediatek: correct voltages for MT7622 and MT7623

The MT6380 regulator typically used together with MT7622 does not
support the current maximum processor and SRAM voltage in the cpufreq
driver (1360000uV).
For MT7622 limit processor and SRAM supply voltages to 1350000uV to
avoid having the tracking algorithm request unsupported voltages from
the regulator.

On MT7623 there is no separate SRAM supply and the maximum voltage used
is 1300000uV. Create dedicated platform data for MT7623 to cover that
case as well.

Fixes: 0883426f ("cpufreq: mediatek: Raise proc and sram max voltage for MT7622/7623")
Suggested-by: Jia-wei Chang <Jia-wei.Chang@mediatek.com>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>