ieee802154: Add support for allowing to answer BEACON_REQ

Accept beaconing configurations from the user which involve answering
beacon requests rather than only passively sending beacons. This may
help devices to find the PAN more quickly.

Signed-off-by: Miquel Raynal <[e-mail]>
Acked-by: Alexander Aring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Stefan Schmidt <[e-mail]>

net/ieee802154/nl802154.c

···
 		NLA_POLICY_RANGE(NLA_U8, NL802154_SCAN_DONE_REASON_FINISHED,
 				 NL802154_SCAN_DONE_REASON_ABORTED),
 	[NL802154_ATTR_BEACON_INTERVAL] =
-		NLA_POLICY_MAX(NLA_U8, IEEE802154_MAX_SCAN_DURATION),
+		NLA_POLICY_MAX(NLA_U8, IEEE802154_ACTIVE_SCAN_DURATION),
 
 #ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
 	[NL802154_ATTR_SEC_ENABLED] = { .type = NLA_U8, },