drm/amdgpu: Remove redundant ras->supported

Remove redundant ras->supported, as this value
is also stored in adev->ras_features.

Use adev->ras_features, as that supercedes "ras",
since the latter is its member.

The dependency goes like this:
ras <== adev->ras_features <== hw_supported,
and is read as "ras depends on ras_features, which
depends on hw_supported." The arrows show the flow
of information, i.e. the dependency update.

"hw_supported" should also live in "adev".

Cc: Alexander Deucher <Alexander.Deucher@amd.com>
Cc: John Clements <john.clements@amd.com>
Cc: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Reviewed-by: John Clements <John.Clements@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>