drm/amd/display: Add comments to improve the code readability

This commit just introduce some basic comments that helps to understand
the overall behavior of some structs.
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -339,7 +339,9 @@ struct stream_resource {
 };
 
 struct plane_resource {
+	/* scl_data is scratch space required to program a plane */
 	struct scaler_data scl_data;
+	/* Below pointers to hw objects are required to enable the plane */
 	struct hubp *hubp;
 	struct mem_input *mi;
 	struct input_pixel_processor *ipp;

drivers/gpu/drm/amd/display/dc/resource/dce80/dce80_resource.c

@@ -56,7 +56,6 @@
 #include "dce/dce_aux.h"
 #include "dce/dce_abm.h"
 #include "dce/dce_i2c.h"
-/* TODO remove this include */
 
 #ifndef mmMC_HUB_RDREQ_DMIF_LIMIT
 #include "gmc/gmc_7_1_d.h"

drivers/gpu/drm/amd/display/dc/resource/dcn201/dcn201_resource.c

@@ -182,6 +182,7 @@ static struct _vcs_dpi_soc_bounding_box_st dcn201_soc = {
 				.socclk_mhz = 1254.0,
 				.dram_speed_mts = 14000.0,
 			},
+			/* state4 is not an actual state, just defines unsupported for dml*/
 			{
 				.state = 4,
 				.dscclk_mhz = 400.0,