sta-info: add last_connected field

Add a last_connected field to the sta_info struct. This field can be
used to determine, if and when a client was last connected to a given
node. This way, other nodes can determine where a client roamed to or
from.

Signed-off-by: David Bauer <mail@david-bauer.net>

remote.h

@@ -72,6 +72,7 @@ enum {
 	APMSG_STA_TIMEOUT,
 	APMSG_STA_SEEN,
 	APMSG_STA_CONNECTED,
+	APMSG_STA_LAST_CONNECTED,
 	__APMSG_STA_MAX
 };
 
@@ -82,6 +83,7 @@ struct apmsg_sta {
 	int signal;
 	int timeout;
 	int seen;
+	int last_connected;
 };
 
 bool parse_apmsg(struct apmsg *msg, struct blob_attr *data);