block: make bio_integrity_map_user() static inline

block: make bio_integrity_map_user() static inline

If CONFIG_BLK_DEV_INTEGRITY isn't set, then the dummy helper must be
static inline to avoid complaints about the function being unused.

Fixes: fe8f4ca7107e ("block: modify bio_integrity_map_user to accept iov_iter as argument")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202411300229.y7h60mDg-lkp@intel.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>