Annotated dprintf as printf-like

ZFS loves using %llu for uint64_t, but that requires a cast to not 
be noisy - which is even done in many, though not all, places.
Also a couple places used %u for uint64_t, which were promoted
to %llu. 

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rich Ercolani <rincebrain@gmail.com>
Closes #12233

module/zfs/sa.c

@@ -1292,7 +1292,7 @@ sa_build_index(sa_handle_t *hdl, sa_buf_type_t buftype)
 			mutex_exit(&sa->sa_lock);
 			zfs_dbgmsg("Buffer Header: %x != SA_MAGIC:%x "
 			    "object=%#llx\n", sa_hdr_phys->sa_magic, SA_MAGIC,
-			    db->db.db_object);
+			    (u_longlong_t)db->db.db_object);
 			return (SET_ERROR(EIO));
 		}
 		sa_byteswap(hdl, buftype);