drm/amd/display: Set ignore_msa_timing flag for freesync modes

- Set ignore_msa_timing_param to 1 only for modes that can support freesync

Signed-off-by: Sylvia Tsai <sylvia.tsai@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>