unix: add Linux network namespace constants

This adds the NETNSA constants from net_namespace.h, used for creating
and querying network namespace IDs.

Fixes golang/go#26330
Change-Id: I786c4c4771be3eddc4fdb830a52e128aa1a2b9fd
Reviewed-on: https://go-review.googlesource.com/124436
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/unix/zerrors_linux_mipsle.go b/unix/zerrors_linux_mipsle.go
index 33b9940..530df8b 100644
--- a/unix/zerrors_linux_mipsle.go
+++ b/unix/zerrors_linux_mipsle.go
@@ -1075,6 +1075,8 @@
 	NETLINK_UNUSED                       = 0x1
 	NETLINK_USERSOCK                     = 0x2
 	NETLINK_XFRM                         = 0x6
+	NETNSA_MAX                           = 0x3
+	NETNSA_NSID_NOT_ASSIGNED             = -0x1
 	NFNETLINK_V0                         = 0x0
 	NFNLGRP_ACCT_QUOTA                   = 0x8
 	NFNLGRP_CONNTRACK_DESTROY            = 0x3