ARM: dts: imx6: pfla02: Fix USB vbus enable pinmuxing

The pinmuxing for the enable pin of the usbh1 node is wrong. It needs to
be muxed as GPIO. While at it, move the pinctrl to the vbus regulator
since it is actually the regulator enable pin.

Signed-off-by: Stefan Riedmueller <s.riedmueller@phytec.de>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>