drm/amd/display: revert max lb lines change

Some hardware revisions do have a max number of lines limitation
not honouring which can cause pstate switch underflow.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Reviewed-by: Eric Bernstein <Eric.Bernstein@amd.com>
Acked-by: Solomon Chiu <solomon.chiu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>