Don't omit soft-reset. During initialization, the driver may need to
perform a soft reset to ensure the phy is ready when the controller
updates the GCTL.PRTCAPDIR or other settings by issuing phy soft-reset.
Many platforms often have access to DCTL register for soft-reset despite
being host-only. If there are actual reported issues from the platforms
that don't expose DCTL registers, then we will need to revisit (perhaps
to teach dwc3 to perform xhci's soft-reset USBCMD.HCRST).