drm/amd/display: Remove unused flag from stream state

[why & how]
Removing unused DSC flag which is incorrect and is not used.
We are only using stream->timing.flags.DSC for DSC's current
state. Stream state as an input parameter and should not contain
any past status flags.
Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Acked-by: Bindu Ramamurthy <bindur12@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_stream.h

@@ -238,7 +238,6 @@ struct dc_stream_state {
 	bool apply_seamless_boot_optimization;
 
 	uint32_t stream_id;
-	bool is_dsc_enabled;
 
 	struct test_pattern test_pattern;
 	union stream_update_flags update_flags;