gfx ras is only available in cerntain ip generations.
Signed-off-by: NHawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: NDennis Li <Dennis.Li@amd.com>
Reviewed-by: NJohn Clements <John.Clements@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>