Latency property is set to firmware during streamon output port,
if set as part of initial configuration by client.
During runtime, the property is set as and when configured by
client.
1. Make the latency property dynamic for decoder.
2. For encoder, the same gets set to firmware with regular
v4l2 set properties.
3. For decoder, set the property explicitly during streamon
output port.
Change-Id: I35990614b95e57f113ddacfc2272cad6ae0dde82
Signed-off-by: Vikash Garodia <vgarodia@codeaurora.org>