drm/amdgpu/sdma: Introduce is_guilty callbacks for sdma GFX and PAGE rings

This patch introduces the `is_guilty` callbacks for the GFX and PAGE rings.
These callbacks check if a ring is guilty of causing a timeout or error.

Suggested-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Jesse Zhang <jesse.zhang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>