drm/amdgpu: add reset source in various cases

To fullfill the reset event description.

Suggested-by: Lijo Lazar <Lijo.Lazar@amd.com>
Signed-off-by: Eric Huang <jinhuieric.huang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>