ARM: dts: at91: sam9x60ek: remove simple-bus for regulators

Keep regulators as individual devices. There is no need to have them
under simple bus. This will throw compilation warnings like:
- unnecessary #address-cells/#size-cells without "ranges" or child "reg"
property.
- node has a unit name, but no reg or ranges property.

While at it move it down a bit in the file to keep entries sorted
alphabetically.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20220826083927.3107272-10-claudiu.beznea@microchip.com