usb: dwc3: gadget: allow Link state changes via debugfs

This is very useful for low level link testing where
we might not have a USB Host stack, only a scope to
verify signal integrity.

Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 8000395..e0e2337 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -117,7 +117,7 @@
 		if (DWC3_DSTS_USBLNKST(reg) == state)
 			return 0;
 
-		usleep_range(500, 1500);
+		udelay(500);
 	}
 
 	dev_vdbg(dwc->dev, "link state change request timed out\n");