Correct gn_index in packet header.

applications/lofar2/libraries/sdp/src/vhdl/sdp_statistics_offload.vhd

@@ -410,7 +410,7 @@ BEGIN
     END IF;
   END PROCESS;
 
-  p_gn_id <= TO_UVEC(p.pn_index, 8);  -- in slv format to ease slicing bit ranges
+  p_gn_id <= TO_UVEC(p.gn_index, 8);  -- in slv format to ease slicing bit ranges
   pp_gn_id <= p_gn_id WHEN rising_edge(dp_clk);  -- pipeline again to ease timing closure
 
   -- Determine info from previous sync interval in which the statistics were