xen/events/fifo: remove a unecessary use of BM()

Since 05a812ac (xen/events/fifo:
correctly align bitops), ready is an unsigned long instead of uint32_t
and the BM() macro is no longer required.
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

drivers/xen/events/events_fifo.c

@@ -330,7 +330,7 @@ static void evtchn_fifo_handle_events(unsigned cpu)
 	ready = xchg(&control_block->ready, 0);
 
 	while (ready) {
-		q = find_first_bit(BM(&ready), EVTCHN_FIFO_MAX_QUEUES);
+		q = find_first_bit(&ready, EVTCHN_FIFO_MAX_QUEUES);
 		consume_one_event(cpu, control_block, q, &ready);
 		ready |= xchg(&control_block->ready, 0);
 	}