IP discovery is only supported in Navi series and onwards.
There is no need to reserve a portion of vram as discovery
tmr region for pre-Navi adapters.
Signed-off-by: NHawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: NLikun Gao <Likun.Gao@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>