drm/amd/display: Add debug option for idle reg checks

[Why]
Leave disabled by default due to sequencing issues around power states
where these flags aren't properly reset.

[How]
Allow re-enabling from DC debug option.
Reviewed-by: Gabe Teeger <gabe.teeger@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/dc.h

@@ -991,6 +991,7 @@ struct dc_debug_options {
 	bool disable_dmub_reallow_idle;
 	bool disable_timeout;
 	bool disable_extblankadj;
+	bool enable_idle_reg_checks;
 	unsigned int static_screen_wait_frames;
 	bool force_chroma_subsampling_1tap;
 };