USB: g_mass_storage: min(...) warning fixed

This patch fixes warning caused by calling min() macro
with arguments of different types:

  drivers/usb/gadget/f_mass_storage.c:623: warning: \
  comparison of distinct pointer types lacks a cast
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Michal Nazarewicz <m.nazarewicz@samsung.com>
Cc: Marek Szyprowski <m.nazarewicz@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/f_mass_storage.c

@@ -620,7 +620,7 @@ static int fsg_setup(struct usb_function *f,
 		*(u8 *) req->buf = fsg->common->nluns - 1;
 
 		/* Respond with data/status */
-		req->length = min(1, w_length);
+		req->length = min((u16)1, w_length);
 		fsg->common->ep0req_name =
 			ctrl->bRequestType & USB_DIR_IN ? "ep0-in" : "ep0-out";
 		return ep0_queue(fsg->common);