drm/amd/display: Fix amdgpu_dm KUnit allmodconfig build

drm/amd/display: Fix amdgpu_dm KUnit allmodconfig build

[Why]
With CONFIG_DRM_AMD_DC_KUNIT_TEST=m, allmodconfig only defines the
_MODULE variant. Four KUnit helper headers gate their declarations
with #ifdef CONFIG_DRM_AMD_DC_KUNIT_TEST, so the declarations vanish
while the matching .c files (driven by IS_ENABLED() via
STATIC_IFN_KUNIT) keep the functions non-static. The build breaks
with implicit declarations and -Werror=missing-prototypes.

amdgpu_dm_crc.h additionally uses symbols that its test file does not
pull in indirectly, amdgpu_dm_colorop_test.c has a copy-paste
duplicate function with the wrong expected bitmask, and the three
colorop TF bitmasks are not exported for modpost.

[How]
- Switch the crc/hdcp/color/psr KUnit guards to IS_ENABLED().
- Make amdgpu_dm_crc.h self-contained (dc_types.h + forward decl).
- Rename the duplicated shaper test back to its intended name and
  fix its expected bitmask.
- Export amdgpu_dm_supported_{degam,shaper,blnd}_tfs via
  EXPORT_IF_KUNIT().

Assisted-by: Copilot:claude-4-opus
Reviewed-by: Alex Hung <alex.hung@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Ray Wu <ray.wu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>