usb: dwc3: core: allow device to runtime_suspend several times

After going through runtime_suspend/runtime_resume
cycle once we would be left with an unbalanced
pm_runtime_get() call. Fix that by making sure that
we try to suspend right after resuming so things are
balanced and device can runtime_suspend again.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 9466431..35d0924 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1192,6 +1192,7 @@
 	}
 
 	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put(dev);
 
 	return 0;
 }