drm/amd/display: only trigger BIOS related assert for older ASICs

[Why]
Some asserts are always hit on startup/Pnp when they should only be used
to indicate when something has gone wrong.

[How]
Ignore result of getting function from bios cmd table for newer asics.

Reviewed-by: Jun Lei <jun.lei@amd.com>
Signed-off-by: Daniel Sa <Daniel.Sa@amd.com>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>