NFSv4.2: xattr cache: remove unused cache struct field

The hash_lock field of the cache structure was a leftover
of a previous iteration of the code. It is now unused,
so remove it.
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/nfs42xattr.c

@@ -67,7 +67,6 @@ struct nfs4_xattr_bucket {
 
 struct nfs4_xattr_cache {
 	struct kref ref;
-	spinlock_t hash_lock;	/* protects hashtable and lru */
 	struct nfs4_xattr_bucket buckets[NFS4_XATTR_HASH_SIZE];
 	struct list_head lru;
 	struct list_head dispose;