experimental change for testing if max line buffer result in better stutter efficiency

for 1080p, LB can hold up to 9 line at 10bpcc, potentially add 10 line time of
latency hiding.
Signed-off-by: NTony Cheng <tony.cheng@amd.com>
Reviewed-by: NYongqiang Sun <yongqiang.sun@amd.com>
Acked-by: NHarry Wentland <Harry.Wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>