scsi: megaraid: Clear READ queue map's nr_queues

scsi: megaraid: Clear READ queue map's nr_queues

The megaraid SCSI driver sets set->nr_maps as 3 if poll_queues is > 0, and
blk-mq actually initializes each map's nr_queues as nr_hw_queues.
Consequently the driver has to clear READ queue map's nr_queues, otherwise
the queue map becomes broken if poll_queues is set as non-zero.

Link: https://lore.kernel.org/r/20220706125942.528533-1-ming.lei@redhat.com
Fixes: 9e4bec5b2a23 ("scsi: megaraid_sas: mq_poll support")
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: sumit.saxena@broadcom.com
Cc: chandrakanth.patil@broadcom.com
Cc: linux-block@vger.kernel.org
Cc: Hannes Reinecke <hare@suse.de>
Reported-by: Guangwu Zhang <guazhang@redhat.com>
Tested-by: Guangwu Zhang <guazhang@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>