rhashtable: Fix RCU dereference annotation in rht_bucket_nested
The current annotation is wrong as it says that we're only called
under spinlock. In fact it should be marked as under either
spinlock or RCU read lock.
Fixes: da20420f83ea ("rhashtable: Add nested tables") Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>