ceph: Use kcalloc for allocating multiple elements

Prefer using kcalloc(a, b) over kzalloc(a * b) as this improves
semantics since kcalloc is intended for allocating an array of memory.

Signed-off-by: Kenneth Lee <[e-mail]>
Reviewed-by: Xiubo Li <[e-mail]>
Signed-off-by: Ilya Dryomov <[e-mail]>

fs/ceph/caps.c

···
 		struct ceph_mds_request *req;
 		int i;
 
-		sessions = kzalloc(max_sessions * sizeof(s), GFP_KERNEL);
+		sessions = kcalloc(max_sessions, sizeof(s), GFP_KERNEL);
 		if (!sessions) {
 			err = -ENOMEM;
 			goto out;