block: always define struct blk_integrity in genhd.h

This will reduce the amount of ifdefs inside the source code for various
drivers and also will reduce the amount of stub functions that were
created for the !CONFIG_BLK_DEV_INTEGRITY case.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Israel Rukshin <israelr@mellanox.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

include/linux/genhd.h

@@ -169,8 +169,6 @@ struct disk_part_tbl {
 struct disk_events;
 struct badblocks;
 
-#if defined(CONFIG_BLK_DEV_INTEGRITY)
-
 struct blk_integrity {
 	const struct blk_integrity_profile	*profile;
 	unsigned char				flags;
@@ -179,8 +177,6 @@ struct blk_integrity {
 	unsigned char				tag_size;
 };
 
-#endif	/* CONFIG_BLK_DEV_INTEGRITY */
-
 struct gendisk {
 	/* major, first_minor and minors are input parameters only,
 	 * don't use directly.  Use disk_devt() and disk_max_parts().