the origin design will use varible of "attr->states" to save node
supported states on current gpu device, but for multi gpu device, when
probe second gpu device, the driver will check attribute node states
from previous gpu device wthether to create attribute node.
it will cause other gpu device create attribute node faild.

1. add member attr_list into amdgpu_device to link supported device attribute node.
2. add new structure "struct amdgpu_device_attr_entry{}" to track device attribute state.
3. drop member "states" from amdgpu_device_attr.

v2:
1. move "attr_list" into amdgpu_pm and rename to "pm_attr_list".
2. refine create & remove device node functions parameter.

fix:
drm/amdgpu: optimize amdgpu device attribute code
Signed-off-by: Kevin Wang <kevin1.wang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>