Pass on g_data_signed, to support preserving sign extension at FIFO output.

.../libraries/sdp/src/vhdl/node_sdp_adc_input_and_timing.vhd

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

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

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

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

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

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

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