drm/amd/display: Acknowledge wm_optimized_required

[Why]
If dc->clk_mgr->funcs->are_clock_states_equal is set, then
wm_optimized_required is never checked. In that case, when going from a
higher mode to a lower mode, wm_optimized_required remains true until
the next mode change.

[How]
 - move from else-if to unconditional or

Signed-off-by: Joshua Aberback <joshua.aberback@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Reviewed-by: Yongqiang Sun <yongqiang.sun@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>