ARM: dts: imx6dl: prtmvt: fix different USB related warnings

Fix USB-related warnings in imx6dl prtmvt device tree by disabling
unused usbphynop1 and usbphynop2 USB PHYs and over-current detection
which is not supported on USB h1 port. This fixes the following warnings
with the current kernel:
usb_phy_generic usbphynop1: dummy supplies not allowed for exclusive requests
usb_phy_generic usbphynop2: dummy supplies not allowed for exclusive requests
imx_usb 2184200.usb: No over current polarity defined

By the way, fix over-current detection on usbotg port.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>