added ring_lib to node_sdp_beamformer

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

@@ -29,12 +29,13 @@
 -- .
 -------------------------------------------------------------------------------
 
-LIBRARY IEEE, common_lib, dp_lib, reorder_lib, st_lib, mm_lib;
+LIBRARY IEEE, common_lib, dp_lib, reorder_lib, st_lib, mm_lib, ring_lib;
 USE IEEE.STD_LOGIC_1164.ALL;
 USE common_lib.common_pkg.ALL;
 USE common_lib.common_mem_pkg.ALL;
 USE common_lib.common_network_layers_pkg.ALL;
 USE dp_lib.dp_stream_pkg.ALL;
+USE ring_lib.ring_pkg.ALL;
 USE work.sdp_pkg.ALL;
 
 ENTITY node_sdp_beamformer IS