ieee802154: add netns support

This patch adds netns support for 802.15.4 subsystem. Most parts are
copy&pasted from wireless subsystem, it has the identically userspace
API.

Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Alexander Aring <aar@pengutronix.de>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/net/nl802154.h

@@ -54,6 +54,8 @@ enum nl802154_commands {
 
 	NL802154_CMD_SET_ACKREQ_DEFAULT,
 
+	NL802154_CMD_SET_WPAN_PHY_NETNS,
+
 	/* add new commands above here */
 
 #ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
@@ -126,6 +128,9 @@ enum nl802154_attrs {
 
 	NL802154_ATTR_PAD,
 
+	NL802154_ATTR_PID,
+	NL802154_ATTR_NETNS_FD,
+
 	/* add attributes here, update the policy in nl802154.c */
 
 #ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL