ARM: dts: lpc32xx: phy3250: remove regulators umbrella device node

The originally added 'regulators' device node has a number of flaws,
to name a few its children has unit addresses but no reg properties,
the regulators are not captured by a device driver due to a missing
'simple-bus' compatible, the regulator names are selected by killing
either alphabetical order or device node grouping property.

The change removes 'regulators' device node and renames the regulators
and labels.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>