media: videobuf2: core: Rename min_buffers_needed field in vb2_queue

Rename min_buffers_needed into min_queued_buffers and update
the documentation about it.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[hverkuil: Drop the change where min_queued_buffers + 1 buffers would be]
[hverkuil: allocated. Now this patch only renames this field instead of making]
[hverkuil: a functional change as well.]
[hverkuil: Renamed 3 remaining min_buffers_needed occurrences.]

media: pci: mgb4: Added Digiteq Automotive MGB4 driver

Digiteq Automotive MGB4 is a modular frame grabber PCIe card for automotive
video interfaces. As for now, two modules - FPD-Link and GMSL - are
available and supported by the driver. The card has two inputs and two
outputs (FPD-Link only).

In addition to the video interfaces it also provides a trigger signal
interface and a MTD interface for FPGA firmware upload.

Signed-off-by: Martin Tůma <martin.tuma@digiteqautomotive.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>