genetlink: only pass array to genl_register_family_with_ops()

As suggested by David Miller, make genl_register_family_with_ops()
a macro and pass only the array, evaluating ARRAY_SIZE() in the
macro, this is a little safer.

The openvswitch has some indirection, assing ops/n_ops directly in
that code. This might ultimately just assign the pointers in the
family initializations, saving the struct genl_family_and_ops and
code (once mcast groups are handled differently.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/genl_magic_func.h b/include/linux/genl_magic_func.h
index 023bc34..4708603 100644
--- a/include/linux/genl_magic_func.h
+++ b/include/linux/genl_magic_func.h
@@ -293,8 +293,7 @@
 
 int CONCAT_(GENL_MAGIC_FAMILY, _genl_register)(void)
 {
-	int err = genl_register_family_with_ops(&ZZZ_genl_family,
-		ZZZ_genl_ops, ARRAY_SIZE(ZZZ_genl_ops));
+	int err = genl_register_family_with_ops(&ZZZ_genl_family, ZZZ_genl_ops);
 	if (err)
 		return err;
 #undef GENL_mc_group