[media] vb2: add out-fence support to QBUF

[media] vb2: add out-fence support to QBUF

If V4L2_BUF_FLAG_OUT_FENCE flag is present on the QBUF call we create
an out_fence and send its fd to userspace on the fence_fd field as a
return arg for the QBUF call.

The fence is signaled on buffer_done(), when the job on the buffer is
finished.

v9:	- remove in-fences changes from this patch (Alex Courbot)
	- improve fence context creation (Hans Verkuil)
	- clean up out fences if vb2_core_qbuf() fails (Hans Verkuil)

v8:
	- return 0 as fence_fd if OUT_FENCE flag not used (Mauro)
	- fix crash when checking not using fences in vb2_buffer_done()

v7:
	- merge patch that add the infrastructure to out-fences into
	this one (Alex Courbot)
	- Do not install the fd if there is no fence. (Alex Courbot)
	- do not report error on requeueing, just WARN_ON_ONCE() (Hans)

v6
	- get rid of the V4L2_EVENT_OUT_FENCE event. We always keep the
	ordering in vb2 for queueing in the driver, so the event is not
	necessary anymore and the out_fence_fd is sent back to userspace
	on QBUF call return arg
	- do not allow requeueing with out-fences, instead mark the
	  buffer
	with an error and wake up to userspace.
	- send the out_fence_fd back to userspace on the fence_fd field

v5:
	- delay fd_install to DQ_EVENT (Hans)
	- if queue is fully ordered send OUT_FENCE event right away
	(Brian)
	- rename 'q->ordered' to 'q->ordered_in_driver'
	- merge change to implement OUT_FENCE event here

v4:
	- return the out_fence_fd in the BUF_QUEUED event(Hans)

v3:	- add WARN_ON_ONCE(q->ordered) on requeueing (Hans)
	- set the OUT_FENCE flag if there is a fence pending (Hans)
	- call fd_install() after vb2_core_qbuf() (Hans)
	- clean up fence if vb2_core_qbuf() fails (Hans)
	- add list to store sync_file and fence for the next queued
	  buffer

v2: check if the queue is ordered.

Change-Id: I5c63827350c67ba703ce6a2b2fb4818bcc721846
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Signed-off-by: Janghyuck Kim <janghyuck.kim@samsung.com>