drm/amd/display: Add KUnit tests for CACP on Linux

[Why]
The CACP enablement on Linux added panel-type detection and CACP
capability logic that was not covered by KUnit tests.

[How]
Export amdgpu_dm_set_panel_type() and amdgpu_dm_update_cacp_caps() for
KUnit via STATIC_IFN_KUNIT/EXPORT_IF_KUNIT and add unit tests covering:
- amdgpu_dm_update_cacp_caps(): IP version gating (including the 3.1.6
  exclusion), eDP/LVDS signal handling, non-eDP signals, and OLED vs LCD
  panel types.
- amdgpu_dm_set_panel_type(): VSDB OLED/MINILED, DPCD oled/miniled bits,
  the DID path (OLED and LCD), the vendor luminance heuristic, and the
  LCD default.

Update the should_create_sysfs backlight tests to reflect the new
OLED/CACP behavior (OLED with/without CACP and LCD eDP panels).

Assisted-by: Copilot:Claude-Opus-4.8
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Chenyu Chen <chen-yu.chen@amd.com>
Signed-off-by: George Zhang <george.zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

0 files changed, 0 insertions, 0 deletions