Revert "drm/amd/display: New path for enabling DPG"

This reverts commit f8e792dc5c45d306a542b9ee991ae80e1c78e4c5

[Why]
We are not implementing the planned new HW
sequence for HUBP disable.

[How]
Revert most related changes to minimize regressions.

Signed-off-by: Wesley Chalmers <[e-mail]>
Reviewed-by: Martin Leung <[e-mail]>
Acked-by: Qingqing Zhuo <[e-mail]>
Tested-by: Daniel Wheeler <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/display/dc/core/dc.c

···
 	if (update->dither_option)
 		stream->dither_option = *update->dither_option;
 
-	if (update->pending_test_pattern)
-		stream->test_pattern = *update->pending_test_pattern;
 	/* update current stream with writeback info */
 	if (update->wb_update) {
 		int i;
···
 							&stream->clamping);
 					odm_pipe = odm_pipe->next_odm_pipe;
 				}
-			}
-
-			if (stream_update->pending_test_pattern) {
-				dc_link_dp_set_test_pattern(stream->link,
-					stream->test_pattern.type,
-					stream->test_pattern.color_space,
-					stream->test_pattern.p_link_settings,
-					stream->test_pattern.p_custom_pattern,
-					stream->test_pattern.cust_pattern_size);
 			}
 
 			/* Full fe update*/

drivers/gpu/drm/amd/display/dc/dc_stream.h

···
 	uint32_t raw;
 };
 
-struct test_pattern {
-	enum dp_test_pattern type;
-	enum dp_test_pattern_color_space color_space;
-	struct link_training_settings const *p_link_settings;
-	unsigned char const *p_custom_pattern;
-	unsigned int cust_pattern_size;
-};
-
 struct dc_stream_state {
 	// sink is deprecated, new code should not reference
 	// this pointer
···
 
 	uint32_t stream_id;
 	bool is_dsc_enabled;
-
-	struct test_pattern test_pattern;
 	union stream_update_flags update_flags;
 };
 
···
 	struct dc_dsc_config *dsc_config;
 	struct dc_transfer_func *func_shaper;
 	struct dc_3dlut *lut3d_func;
-	struct test_pattern *pending_test_pattern;
 };
 
 bool dc_is_stream_unchanged(