[WHAT]
Add KUnit tests for the per-source IRQ state callbacks (HPD, pflip,
CRTC, vline0, vupdate, dmub outbox/trace), the immediate and scheduled
IRQ work paths, and amdgpu_dm_outbox_init.
Assisted-by: Copilot:Claude-Opus-4.8 Reviewed-by: Bhawanpreet Lakha <bhawanpreet.lakha@amd.com> Signed-off-by: Alex Hung <alex.hung@amd.com> Signed-off-by: George Zhang <george.zhang@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>