-Fixed typo in c_ram_dat_w.

libraries/dsp/st/src/vhdl/mmp_st_histogram.vhd

libraries/dsp/st/src/vhdl/st_histogram.vhd

libraries/dsp/st/tb/vhdl/tb_mmp_st_histogram.vhd

libraries/dsp/st/tb/vhdl/tb_st_histogram.vhd