ceph: fix a comment typo

Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Yan, Zheng <zyan@redhat.com>

fs/ceph/cache.c

@@ -88,7 +88,7 @@ static uint16_t ceph_fscache_inode_get_key(const void *cookie_netfs_data,
 	const struct ceph_inode_info* ci = cookie_netfs_data;
 	uint16_t klen;
 
-	/* use ceph virtual inode (id + snaphot) */
+	/* use ceph virtual inode (id + snapshot) */
 	klen = sizeof(ci->i_vino);
 	if (klen > maxbuf)
 		return 0;