drm/amd/display: Add KUnit tests for crtc set_vblank

Add coverage for the amdgpu_dm_crtc_set_vblank() paths reached through
amdgpu_dm_crtc_enable_vblank() and amdgpu_dm_crtc_disable_vblank():

- dm_test_crtc_enable_vblank_full_path: VRR-active enable that walks the
  vupdate-irq branch and acquires the crtc/pageflip IRQ references.
- dm_test_crtc_enable_vblank_vupdate_busy: vupdate IRQ rejection aborts
  the enable with -EBUSY.
- dm_test_crtc_enable_vblank_crtc_irq_error: crtc IRQ acquire failure
  aborts the enable with -ENOENT.
- dm_test_crtc_enable_vblank_in_reset: an in-progress GPU reset returns
  early before the vblank workqueue branch.
- dm_test_crtc_disable_vblank_vrr: the VRR disable path turns the vupdate
  IRQ off and releases both IRQ references.

Add shared IRQ-source stubs and setup helpers so amdgpu_irq_get()/put()
succeed without hardware access.

Assisted-by: Copilot:Claude-Opus-4.8
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Bhawanpreet Lakha <bhawanpreet.lakha@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

0 files changed, 0 insertions, 0 deletions