GCC 6.1 complains about this.
drivers/usb/gadget/dwc2_udc_otg.c:72:19: warning: 'driver_desc'
defined but not used [-Wunused-const-variable=]
static const char driver_desc[] = DRIVER_DESC;
^~~~~~~~~~~
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>