usb: dwc3: drd: Don't check against CONFIG_OF

usb: dwc3: drd: Don't check against CONFIG_OF

The CONFIG_OF maybe set, but it may not be applicable to a device. In
such case, checking against that can cause the device fail to
initialize. Check against the device node (device->of_node) instead.

Fixes: a102f07e4edf ("usb: dwc3: drd: Add support for usb-conn-gpio based usb-role-switch")
Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/9f15580ad5810b1e5f31c241b35ebedfbfc30a3f.1644964864.git.Thinh.Nguyen@synopsys.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>