libceph: fix ceph_pagelist_reserve() comment typo

The double `without' is duplicated in the comment, remove one.

Signed-off-by: Jason Wang <wangborong@cdjrlc.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

net/ceph/pagelist.c

@@ -96,7 +96,7 @@ int ceph_pagelist_append(struct ceph_pagelist *pl, const void *buf, size_t len)
 EXPORT_SYMBOL(ceph_pagelist_append);
 
 /* Allocate enough pages for a pagelist to append the given amount
- * of data without without allocating.
+ * of data without allocating.
  * Returns: 0 on success, -ENOMEM on error.
  */
 int ceph_pagelist_reserve(struct ceph_pagelist *pl, size_t space)