reset functionality addition to fix frequency misalignment

The output speadify blocks have a reset input to flush internal state
and prevent mislabelling of output data. This is attached to the msb
of the bf[n]_cfg[m] register from version 365. Basic test of eyeballing
output spectrum for correlator and beamformer performed.
Merge branch 'master' of https://github.com/ska-sa/corr