new_codec: source clean up

new_codec: source clean up

Changed some variables's name and resolve a sync problem between each job.
In addition, added two ways to handle decoding or encoding data with device memory.

At first, each codec request uses 24MB memory size in a fixed way.
It means that each codec request occupies its own memory region.
If the device memory is used up to 24MB, other codec request uses other memory region in a shared way.
It means that more than 2 codec requests use the memory region sequentially.

Change-Id: I0497d607cf46b98e403ed0d6d7530ea2023212a8
Signed-off-by: Kitae Kim <kt920.kim@samsung.com>