media: videobuf2-core: add error handling for fence

media: videobuf2-core: add error handling for fence

Vb2-core supports in-fence and out-fence for buffer synchronization.
However, in-fence might not be signaled by unexpected situation. Current
logic is waiting for fence signaling infinitely.

This patch added timer when in-fence without signaled is coming, and it
will be expired if callback for in-fence would not be called, which
means in-fence was not signaled during 1000 ms. This case is timeout and
buffer is passed into driver by buf_queue callback, however, it would be
marked with error status.

To support this error handling, vb2-core logic is changed to use
workqueue to avoid calling buf_queue callback in interrupt context.

Change-Id: Icd533c355fa83605e958c8058a676256a6940f14
Signed-off-by: Janghyuck Kim <janghyuck.kim@samsung.com>