drm/amd/display: add support for chroma offset

[Why]
Adding support for chroma subsampling offset (cositing) in scaler
calculations to adjust reference point where we determine post-scaling
chroma value in YUV420 surfaces.

[How]
Add support for cositing options: NONE, LEFT and TOPLEFT Add debug
option force_cositing and set default to TOPLEFT to maintain same
behaviour as without offset support.

Reviewed-by: Jun Lei <[e-mail]>
Acked-by: Rodrigo Siqueira <[e-mail]>
Signed-off-by: Samson Tam <[e-mail]>
Tested-by: Daniel Wheeler <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

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

···
 	unsigned int static_screen_wait_frames;
 	bool force_chroma_subsampling_1tap;
 	bool disable_422_left_edge_pixel;
+	unsigned int force_cositing;
 };
 
 struct gpu_info_soc_bounding_box_v1_0;
···
 	struct tg_color visual_confirm_color;
 
 	bool is_statically_allocated;
+	enum chroma_cositing cositing;
 };
 
 struct dc_plane_info {
···
 	int  global_alpha_value;
 	bool input_csc_enabled;
 	int layer_index;
+	enum chroma_cositing cositing;
 };
 
 #include "dc_stream.h"

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

···
 	SCANNING_TYPE_UNDEFINED
 };
 
+enum chroma_cositing {
+	CHROMA_COSITING_NONE,
+	CHROMA_COSITING_LEFT,
+	CHROMA_COSITING_TOPLEFT,
+	CHROMA_COSITING_COUNT
+};
+
 struct dc_crtc_timing_flags {
 	uint32_t INTERLACE :1;
 	uint32_t HSYNC_POSITIVE_POLARITY :1; /* when set to 1,