usb: cdns3: gadget: unsigned int is dereferenced as a wider unsigned long

It is reported by Coverity scan, and fixed it by declare the reg as
unsigned long.

Reviewed-by: Jun Li <jun.li@nxp.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>
Acked-by: Roger Quadros <rogerq@ti.com>
Link: https://lore.kernel.org/r/20200623031001.8469-3-peter.chen@nxp.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>