ARM: dts: Improve Peach Pit and Pi power scheme

The DeviceTree files for the Peach Pit and Pi machines have
a simplistic model of the connections between the different
regulators since not all the tps65090 regulators get their
input supply voltage from the VDC. DCDC1-3, LD0-1 and fet7
parent supply is indded VDC but the fet1-6 get their input
supply from the DCDC1 and DCDC2 output voltage rails.

Update the DeviceTree to better reflect the real connections
between tps65090 regulators. Having this information in the
DTS is useful since FETs are switches that don't provide an
output voltage so the regulator core needs to fetch the FET
parent output voltage if the child voltage is queried.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Acked-by: Mark Brown <broonie@linaro.org>
Acked-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>