USB: f_ncm: ncm_bitrate (speed) is unsigned

[ 190.544755] configfs-gadget gadget: notify speed -44967296

This is because 4250000000 - 2**32 is -44967296.

Fixes: 9f6ce4240a2b ("usb: gadget: f_ncm.c added")
Cc: Brooke Basile <[e-mail]>
Cc: Bryan O'Donoghue <[e-mail]>
Cc: Felipe Balbi <[e-mail]>
Cc: Lorenzo Colitti <[e-mail]>
Cc: Yauheni Kaliuta <[e-mail]>
Cc: Linux USB Mailing List <[e-mail]>
Acked-By: Lorenzo Colitti <[e-mail]>
Signed-off-by: Maciej Żenczykowski <[e-mail]>
Cc: stable <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/gadget/function/f_ncm.c

···
 		data[0] = cpu_to_le32(ncm_bitrate(cdev->gadget));
 		data[1] = data[0];
 
-		DBG(cdev, "notify speed %d\n", ncm_bitrate(cdev->gadget));
+		DBG(cdev, "notify speed %u\n", ncm_bitrate(cdev->gadget));
 		ncm->notify_state = NCM_NOTIFY_CONNECT;
 		break;
 	}