This PR implements a few changes related to the accumulation offset
which is new in MI200. Previously MI100 contained two vector register
files: the architectural and accumulation register files. These have now
been unified and the architectural register file is twice the size. As a
result of this the dispatch packet set an offset into the unified vector
register file for where the former accumulation registers would go. The
changes are:
- Calculate the accumulation offset from dispatch packet and store in
HSA task.
- Update the accumulation move instructions (v_accvgpr_read/write) to
use it.
- Update the current MFMA instructions to use it.
- Make the MFMA examples more clean.