drm/amd/display: Reset freesync config before update new state

[Why]
Sometimes the new_crtc_state->vrr_infopacket did not sync up with the
current state.
It will affect the update_freesync_state_on_stream() does not update
the state correctly.

[How]
Reset the freesync config before get_freesync_config_for_crtc() to
make sure we have the correct new_crtc_state for VRR.

Reviewed-by: Sun peng Li <sunpeng.li@amd.com>
Signed-off-by: Jerry Zuo <jerry.zuo@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>