USB_VDD_1P0 must be tied to 1V or the platform voltage (based on whatever the SOC core digital power supply is). USB_VDD_3P3 can be left floating.
If USB is not to be used at all, keep the following USB signals floating : USB1_IBIAS_REXT, USB2_IBIAS_REXT, USB1_VDD_1P8_DECAP and USB2_VDD_1P8_DECAP, USB1_VDD_3P3, USB2_VDD_3P3.