ARM: dts: imx6qdl-apf6dev: 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-apf6dev.dtb: Warning (simple_bus_reg): Node /regulators/3p3v missing or empty reg/ranges property
arch/arm/boot/dts/imx6dl-apf6dev.dtb: Warning (simple_bus_reg): Node /regulators/usb-h1-vbus missing or empty reg/ranges property
arch/arm/boot/dts/imx6dl-apf6dev.dtb: Warning (simple_bus_reg): Node /regulators/usb-otg-vbus missing or empty reg/ranges property

Cc: Sébastien Szymanski <sebastien.szymanski@armadeus.com>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>