rhashtable: simplify INIT_RHT_NULLS_HEAD()

The 'ht' and 'hash' arguments to INIT_RHT_NULLS_HEAD() are
no longer used - so drop them.  This allows us to also
remove the nhash argument from nested_table_alloc().

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index d9f719a..3f3a182 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -75,7 +75,7 @@
 	struct rhash_head __rcu *buckets[] ____cacheline_aligned_in_smp;
 };
 
-#define INIT_RHT_NULLS_HEAD(ptr, ht, hash) \
+#define INIT_RHT_NULLS_HEAD(ptr)	\
 	((ptr) = (typeof(ptr)) NULLS_MARKER(0))
 
 static inline bool rht_is_a_nulls(const struct rhash_head *ptr)