arm64: dts: meson: odroid-c2: p5v0 is the main 5V power input

As per the schematic Monolithic Power Systems MP2161GJ-C499
supply a fixed output voltage of 5.0V. This supplies linked
to VDD_EE, HDMI_P5V0, USB_POWER, VCCK, VDDIO_AO1V8, VDDIO_AO3V3,
VDD3V3, DDR3_1V5 according to the schematics.

Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>