In order to surface the ASIC revision to user level, we want
to put it into the HSA topology. This can be because different
ASIC revisions may require user-level software to do different
things (e.g. patch code for things that are changed in later
hardware revisions).

The ASIC revision from the hardware is maximum of 4 bits at this
time, so put it into 4 of the open bits in the HSA capability.
Then user-level software can use this capability information to
know -- for each ASIC -- what revision-based things must be done.
Signed-off-by: Joseph Greathouse <Joseph.Greathouse@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>