libmix: A fix to enable low delay mode for VP8

BZ: 154044

VP8 doesn't have config data, low delay mode should be
enabled when calling startVA().

Change-Id: Iaed76040ce9e31052f63f5ba89cd1c57dc8cf3ed
Signed-off-by: Tianmi Chen <tianmi.chen@intel.com>
1 file changed