increased read latency of mms_dp_gain_serial_arr

...ons/lofar2/libraries/sdp/src/vhdl/node_sdp_filterbank.vhd

libraries/base/dp/src/vhdl/mms_dp_gain_serial_arr.vhd

libraries/base/dp/tb/vhdl/tb_mms_dp_gain_serial_arr.vhd