drm/amd/display: Don't use ROM for output TF if GAMMA_CS_TFM_1D

We can’t use hardcoded SRGB ROM for output TF if we have GAMMA_CS_TFM_1D
(unless we know 1D LUT is identity), so we never want to return here early.
We apply the LUT part of ColorTransform3x4 only in apply_lut_1d() which is
called near the end of that function.
Signed-off-by: Hugo Hu <hugo.hu@amd.com>
Reviewed-by: Krunoslav Kovac <Krunoslav.Kovac@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/modules/color/color_gamma.c

@@ -1569,7 +1569,8 @@ bool mod_color_calculate_regamma_params(struct dc_transfer_func *output_tf,
 			output_tf->tf == TRANSFER_FUNCTION_SRGB) {
 		if (ramp == NULL)
 			return true;
-		if (ramp->is_identity || (!mapUserRamp && ramp->type == GAMMA_RGB_256))
+		if ((ramp->is_identity && ramp->type != GAMMA_CS_TFM_1D) ||
+				(!mapUserRamp && ramp->type == GAMMA_RGB_256))
 			return true;
 	}