usb: xhci: dwc3: Adding reset delay requirement as per dwc3 databook

As per dwc3 databook, delay is required before taking the core out of reset.
This delay is required so that the PHY are stable, and then we can take core
out of reset.

Reference is taken from linux dwc3 code, file: drivers/usb/dwc3/core.c.

Signed-off-by: Sriram Dash <sriram.dash@freescale.com>
Signed-off-by: Rajesh Bhagat <rajesh.bhagat@freescale.com>

drivers/usb/host/xhci-dwc3.c

@@ -44,6 +44,8 @@ void dwc3_core_soft_reset(struct dwc3 *dwc3_reg)
 	/* reset USB3 phy - if required */
 	dwc3_phy_reset(dwc3_reg);
 
+	mdelay(100);
+
 	/* After PHYs are stable we can take Core out of reset state */
 	clrbits_le32(&dwc3_reg->g_ctl, DWC3_GCTL_CORESOFTRESET);
 }