ARM: dts: imx6qdl-aristainetos: Move regulators out of simple-bus

It is not recommended to place regulator nodes inside simple-bus, so
move them out in order to fix the following build warnings with W=1:

arch/arm/boot/dts/imx6dl-aristainetos_4.dtb: Warning (unit_address_vs_reg): Node /regulators/regulator@0 has a unit name, but no reg property
arch/arm/boot/dts/imx6dl-aristainetos_4.dtb: Warning (unit_address_vs_reg): Node /regulators/regulator@1 has a unit name, but no reg property
arch/arm/boot/dts/imx6dl-aristainetos_4.dtb: Warning (unit_address_vs_reg): Node /regulators/regulator@2 has a unit name, but no reg property
arch/arm/boot/dts/imx6dl-aristainetos_4.dtb: Warning (unit_address_vs_reg): Node /regulators/regulator@3 has a unit name, but no reg property

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Tested-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>