drm/amd/display: Add missing dml2 init value for dcn35

[Why]
For lighting up, some dml2 params needs to be initialized.
One of them escaped initial patch under:
"drm/amd/display: Add DCN35 DML2 support"

[How]
Add missing initialization.

Fixes: 115009d1 ("drm/amd/display: Add DCN35 DML2 support")
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Acked-by: Hersen Wu <hersenxs.wu@amd.com>
Signed-off-by: Roman Li <roman.li@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/dml2/dml2_translation_helper.c

@@ -231,6 +231,7 @@ void dml2_init_socbb_params(struct dml2_context *dml2, const struct dc *in_dc, s
 		out->num_chans = 4;
 		out->round_trip_ping_latency_dcfclk_cycles = 106;
 		out->smn_latency_us = 2;
+		out->dispclk_dppclk_vco_speed_mhz = 3600;
 		break;
 
 	case dml_project_dcn351: