ARM: dts: fix usb pin control for imx-rex dts

This fixes a duplicated pin control causing this error:

imx6q-pinctrl 20e0000.iomuxc: pin MX6Q_PAD_GPIO_1 already
requested by regulators:regulator@2; cannot claim for 2184000.usb
imx6q-pinctrl 20e0000.iomuxc: pin-137 (2184000.usb) status -22
imx6q-pinctrl 20e0000.iomuxc: could not request pin 137
(MX6Q_PAD_GPIO_1) from group usbotggrp  on device 20e0000.iomuxc
imx_usb 2184000.usb: Error applying setting, reverse things
back
imx6q-pinctrl 20e0000.iomuxc: pin MX6Q_PAD_EIM_D31 already
requested by regulators:regulator@1; cannot claim for 2184200.usb
imx6q-pinctrl 20e0000.iomuxc: pin-52 (2184200.usb) status -22
imx6q-pinctrl 20e0000.iomuxc: could not request pin 52 (MX6Q_PAD_EIM_D31)
from group usbh1grp  on device 20e0000.iomuxc
imx_usb 2184200.usb: Error applying setting, reverse things
back

Signed-off-by: Felipe F. Tonello <eu@felipetonello.com>
Fixes: e2047e33 ("ARM: dts: add initial Rex Pro board support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>