dm: Remove max_write_zeroes_granularity

The max_write_zeroes_granularity boolean of struct dm_target is used in
__process_abnormal_io() but never set by any target. Remove this field
and the dead code using it.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

drivers/md/dm.c

@@ -1664,8 +1664,6 @@ static blk_status_t __process_abnormal_io(struct clone_info *ci,
 	case REQ_OP_WRITE_ZEROES:
 		num_bios = ti->num_write_zeroes_bios;
 		max_sectors = limits->max_write_zeroes_sectors;
-		if (ti->max_write_zeroes_granularity)
-			max_granularity = max_sectors;
 		break;
 	default:
 		break;

include/linux/device-mapper.h

@@ -369,12 +369,6 @@ struct dm_target {
 	 */
 	bool max_secure_erase_granularity:1;
 
-	/*
-	 * Set if this target requires that write_zeroes be split on
-	 * 'max_write_zeroes_sectors' boundaries.
-	 */
-	bool max_write_zeroes_granularity:1;
-
 	/*
 	 * Set if we need to limit the number of in-flight bios when swapping.
 	 */