[COMMON] g2d: add support for dma-buf fence

[COMMON] g2d: add support for dma-buf fence

G2D driver needs to wait for the fences to be signaled to schedlue a
task if they are attached to layers of that task. Users may needs G2D
driver to deliver fences to know when the G2D H/W completes processing
on a job.
G2D driver impelements such buffer synchronization with dma-buf fence
and exports the fence to sync_file to give the fences for the job
completion, which are called release fences. The driver does not
generate a new fence for every single buffers that needs release
fences. Instead, it generates a single release fence and exports to
multiple sync_files as many as the user required. It reduces the use
of resources and simplifies the fence management in the driver.

Change-Id: I31f2c5156b29d7a1bb8096b4c34811cbc75c679a
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>