drm/amd/display: For stereo keep "FLIP_ANY_FRAME"

[Description]
Observed in stereomode that programming FLIP_LEFT_EYE
can cause hangs. Keep FLIP_ANY_FRAME in stereo mode so
the surface flip can take place before left or right eye

Reviewed-by: Martin Leung <Martin.Leung@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Alvin Lee <alvin.lee2@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>