drm/amdgpu: add field indicating if has PCIE atomics support

The new field in amdgpu device is used to record whether the
system has PCIE atomics support. The field can be exposed to
UMD or kfd whether PCIE atomics have supported.

Signed-off-by: Jack Xiao <Jack.Xiao@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>