When mapping in the collationBuff we only need to supply CL_MAP_WRITE
and not CL_MAP_WRITE_INVALIDATE_REGION since we don't care to
preserve the contents of the collation buff as input to the
collation kernel.
It seems that whenever you have an HOST_PTR input buffer to be
"transferred" from the host to the GPU, whose contents must be
preserved, you must map it with WRITE_INVALIDATE_REGION on the
RPi5.
This makes little sense, but we'll have to let it be for now.
At least the code works now and we don't have to abandon using
OpenCL.
This method takes an input assembly buffer and selects which
OpenCL kernels need to be executed on that buffer to transform
the input data into the eventual output StimulusFrame for the
current timeslice period.