drm/amd/display: Enable reallow for idle on DCN35

[Why]
It was previously disabled for stability purposes, but command
submission causes residency issues in IPS video playback.

[How]
Enable the disallow/reallow pattern back. There's additional checks
now in DMCUB that should make this safer stability wise.
Reviewed-by: Duncan Ma <duncan.ma@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c

@@ -783,7 +783,7 @@ static const struct dc_debug_options debug_defaults_drv = {
 	.psp_disabled_wa = true,
 	.ips2_eval_delay_us = 2000,
 	.ips2_entry_delay_us = 800,
-	.disable_dmub_reallow_idle = true,
+	.disable_dmub_reallow_idle = false,
 	.static_screen_wait_frames = 2,
 };