rxrpc: Turn connection #defines into enums and put outside struct def

Turn the connection event and state #define lists into enums and move
outside of the struct definition.

Whilst we're at it, change _SERVER to _SERVICE in those identifiers and add
EV_ into the event name to distinguish them from flags and states.

Also add a symbol indicating the number of states and use that in the state
text array.

Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c
index d7e183c..b9c39b8 100644
--- a/net/rxrpc/conn_event.c
+++ b/net/rxrpc/conn_event.c
@@ -195,8 +195,8 @@
 		read_lock_bh(&conn->lock);
 		spin_lock(&conn->state_lock);
 
-		if (conn->state == RXRPC_CONN_SERVER_CHALLENGING) {
-			conn->state = RXRPC_CONN_SERVER;
+		if (conn->state == RXRPC_CONN_SERVICE_CHALLENGING) {
+			conn->state = RXRPC_CONN_SERVICE;
 			for (loop = 0; loop < RXRPC_MAXCALLS; loop++)
 				rxrpc_call_is_secure(conn->channels[loop]);
 		}
@@ -268,7 +268,7 @@
 
 	rxrpc_get_connection(conn);
 
-	if (test_and_clear_bit(RXRPC_CONN_CHALLENGE, &conn->events)) {
+	if (test_and_clear_bit(RXRPC_CONN_EV_CHALLENGE, &conn->events)) {
 		rxrpc_secure_connection(conn);
 		rxrpc_put_connection(conn);
 	}