drm/amd/display: Fix shaper using bad LUT params

[Why]
LUT params are not cleared after setting blend TF, which can lead to
same params being used for the shaper, if the shaper func is bypassed.

[How]
Set lut_params to NULL after program_1dlut.
Reviewed-by: Krunoslav Kovac <krunoslav.kovac@amd.com>
Acked-by: Roman Li <roman.li@amd.com>
Signed-off-by: Ilya Bakoulin <ilya.bakoulin@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/hwss/dcn32/dcn32_hwseq.c

@@ -494,6 +494,7 @@ bool dcn32_set_mcm_luts(
 		}
 	}
 	result = mpc->funcs->program_1dlut(mpc, lut_params, mpcc_id);
+	lut_params = NULL;
 
 	// Shaper
 	if (plane_state->in_shaper_func) {