usb: dwc3: Add SoftReset PHY synchonization delay

[ Upstream commit fab3833338779e1e668bd58d1f76d601657304b8 ]

>From DWC_usb31 programming guide section 1.3.2, once DWC3_DCTL_CSFTRST
bit is cleared, we must wait at least 50ms before accessing the PHY
domain (synchronization delay).

Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>