drm/amdgpu: share struct amdgpu_pm_state_type with powerplay module

rename amdgpu_pm_state_type to amd_pm_state_type

Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Acked-by: Jammy Zhou <Jammy.Zhou@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>