Move DWC2 driver out of staging

The DWC2 driver should now be in good enough shape to move out of
staging. I have stress tested it overnight on RPI running mass
storage and Ethernet transfers in parallel, and for several days
on our proprietary PCI-based platform.

Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Cc: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
index 2642b8a..7eb909a 100644
--- a/drivers/usb/Kconfig
+++ b/drivers/usb/Kconfig
@@ -108,6 +108,8 @@
 
 source "drivers/usb/dwc3/Kconfig"
 
+source "drivers/usb/dwc2/Kconfig"
+
 source "drivers/usb/chipidea/Kconfig"
 
 comment "USB port drivers"