drm/amdkfd: Put ASIC revision into HSA capability

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>