[TIPC] Updated link priority macros

Added macros for min/default/max link priority in tipc_config.h.
Also renamed TIPC_NUM_LINK_PRI to TIPC_MEDIA_LINK_PRI since that
is a more accurate description of what it is used for.

Signed-off-by: Per Liden <per.liden@ericsson.com>
diff --git a/net/tipc/link.c b/net/tipc/link.c
index 7265f4b..d1e1ae6 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -2812,7 +2812,8 @@
 		}
 		break;
 	case TIPC_CMD_SET_LINK_PRI: 
-		if (new_value < TIPC_NUM_LINK_PRI) {
+		if ((new_value >= TIPC_MIN_LINK_PRI) &&
+		    (new_value <= TIPC_MAX_LINK_PRI)) {
 			l_ptr->priority = new_value;
 			link_send_proto_msg(l_ptr, STATE_MSG, 
 					    0, 0, 0, new_value, 0);