ARM: dts: imx6: phyFLEX: USB VBUS control is active-high

The fixed-regulator bindings require a separate property enable-active-high,
the standard gpio phandle property polarity setting is ignored.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Fixes: 4fe69a93 ("ARM: dts: Add Phytec pfla02 with i.MX6 DualLite/Solo")
Cc: stable@vger.kernel.org
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>