drm/amd/display: fix typos for dcn20_funcs and dcn21_funcs struct

In dcn20_funcs and dcn21_funcs struct, the member ".dsc_pg_control = NULL"
should be removed due to .dsc_pg_control be assigned to dcn20_dsc_pg_control.
Signed-off-by: Stanley.Yang <Stanley.Yang@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_init.c

@@ -111,7 +111,6 @@ static const struct hwseq_private_funcs dcn20_private_funcs = {
 	.enable_power_gating_plane = dcn20_enable_power_gating_plane,
 	.dpp_pg_control = dcn20_dpp_pg_control,
 	.hubp_pg_control = dcn20_hubp_pg_control,
-	.dsc_pg_control = NULL,
 	.update_odm = dcn20_update_odm,
 	.dsc_pg_control = dcn20_dsc_pg_control,
 	.get_surface_visual_confirm_color = dcn10_get_surface_visual_confirm_color,

drivers/gpu/drm/amd/display/dc/dcn21/dcn21_init.c

@@ -119,7 +119,6 @@ static const struct hwseq_private_funcs dcn21_private_funcs = {
 	.enable_power_gating_plane = dcn20_enable_power_gating_plane,
 	.dpp_pg_control = dcn20_dpp_pg_control,
 	.hubp_pg_control = dcn20_hubp_pg_control,
-	.dsc_pg_control = NULL,
 	.update_odm = dcn20_update_odm,
 	.dsc_pg_control = dcn20_dsc_pg_control,
 	.get_surface_visual_confirm_color = dcn10_get_surface_visual_confirm_color,