Block drivers: make IOCTL request unsigned long

The block driver protocol and libblockdriver's bdr_ioctl hook are
changed, as well as the users of this hook. Other parts of the system
are expected to change accordingly eventually, since the ioctl(2)
prototype has been aligned with NetBSD's.

Change-Id: Ide46245b22cfa89ed267a38088fb0ab7696eba92

drivers/filter/main.c

@@ -267,7 +267,7 @@ static int do_ioctl(message *m)
 		break;
 
 	default:
-		printf("Filter: unknown ioctl request: %d!\n",
+		printf("Filter: unknown ioctl request: %ld!\n",
 			m->BDEV_REQUEST);
 		return ENOTTY;
 	}