For multichannel configuration, the CONFIG channel expects a single pulse on
s_axis_config_tlast to indicate the last sample in a sequence of
channels (a “vector”). If s_axis_config_tlast is asserted when the core
does not expect it to be, event_s_config_tlast_unexpected is asserted.
If the s_axis_config_tlast pulse is not asserted with the configuration
data of the last channel, event_s_config_tlast_missing is asserted.