Move ras_hw_supported into struct amdgpu_dev.
The dependency is:
struct amdgpu_ras <== struct amdgpu_dev <== ASIC,
read as "struct amdgpu_ras depends on struct
amdgpu_dev, which depends on the hardware."

This can be loosely understood as, "if RAS is
supported, which is property of the ASIC (struct
amdgpu_dev), then we can access struct
amdgpu_ras."

v2: Fix a typo: must binary AND in ternary cond
    in amdgpu_ras.c

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>