block: also return bio_integrity_payload * from stubs

struct bio_integrity_payload is defined unconditionally. No need to
return void * from bio_integrity() and bio_integrity_alloc().

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240702151047.1746127-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Christoph Hellwig

include/linux/bio-integrity.h

@@ -85,7 +85,7 @@ void bio_integrity_init(void);
 
 #else /* CONFIG_BLK_DEV_INTEGRITY */
 
-static inline void *bio_integrity(struct bio *bio)
+static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
 {
 	return NULL;
 }
@@ -138,8 +138,8 @@ static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 	return false;
 }
 
-static inline void *bio_integrity_alloc(struct bio *bio, gfp_t gfp,
-		unsigned int nr)
+static inline struct bio_integrity_payload *
+bio_integrity_alloc(struct bio *bio, gfp_t gfp, unsigned int nr)
 {
 	return ERR_PTR(-EINVAL);
 }