usb: gadget: udc: renesas_usb3: Fix __le16 warnings

This patch fixes the following sparse warnings by using
a macro and a suitable variable type.

drivers/usb/gadget/udc/renesas_usb3.c:1547:17: warning: restricted __le16 degrades to integer
drivers/usb/gadget/udc/renesas_usb3.c:1550:43: warning: incorrect type in argument 2 (different base types)
drivers/usb/gadget/udc/renesas_usb3.c:1550:43:    expected unsigned short [usertype] addr
drivers/usb/gadget/udc/renesas_usb3.c:1550:43:    got restricted __le16 [usertype] wValue
drivers/usb/gadget/udc/renesas_usb3.c:1607:24: warning: incorrect type in assignment (different base types)
drivers/usb/gadget/udc/renesas_usb3.c:1607:24:    expected unsigned short [assigned] [usertype] status
drivers/usb/gadget/udc/renesas_usb3.c:1607:24:    got restricted __le16 [usertype]
drivers/usb/gadget/udc/renesas_usb3.c:1775:17: warning: restricted __le16 degrades to integer

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>