SUNRPC: Store the hashtable size in struct rpc_cred_cache

Cleanup in preparation for allowing the user to determine the maximum hash
table size.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

include/linux/sunrpc/auth.h

@@ -65,6 +65,7 @@ struct rpc_cred {
 #define RPC_CREDCACHE_NR	(1 << RPC_CREDCACHE_HASHBITS)
 struct rpc_cred_cache {
 	struct hlist_head	hashtable[RPC_CREDCACHE_NR];
+	unsigned int		hashbits;
 	spinlock_t		lock;
 };