dm integrity: fix ppc64le warning

Otherwise:

In file included from drivers/md/dm-integrity.c:13:
drivers/md/dm-integrity.c: In function 'dm_integrity_status':
drivers/md/dm-integrity.c:3061:10: error: format '%llu' expects
argument of type 'long long unsigned int', but argument 4 has type
'long int' [-Werror=format=]
   DMEMIT("%llu %llu",
          ^~~~~~~~~~~
    atomic64_read(&ic->number_of_mismatches),
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/device-mapper.h:550:46: note: in definition of macro 'DMEMIT'
      0 : scnprintf(result + sz, maxlen - sz, x))
                                              ^
cc1: all warnings being treated as errors

Fixes: 7649194a

 ("dm integrity: remove sector type casts")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>