sd: simplify the disable case in sd_config_discard

sd: simplify the disable case in sd_config_discard

Fall through to the main call to blk_queue_max_discard_sectors given that
max_blocks has been initialized to zero above instead of duplicating the
call.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240531074837.1648501-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>