ARM: dts: meson8m2: add resets for the power domain controller

The Meson8m2 SoCs has introduced additional reset lines for the VPU
compared to Meson8. Also it uses a slightly different VPU clock
frequency compared to Meson8 since it can now achieve 364MHz thanks to
the addition of the GP_PLL.
Add the reset lines, VPU clock configuration and update the compatible
string so the implementation differences can be managed.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lore.kernel.org/r/20200620161010.23171-3-martin.blumenstingl@googlemail.com