[media] bdisp: 2D blitter driver using v4l2 mem2mem framework

This v4l2 mem2mem driver is a 2D blitter for STMicroelectronics SoC.
It uses the v4l2 mem2mem framework.

The following features are supported and tested:
- Color format conversion (RGB32, RGB24, RGB16, NV12, YUV420P)
- Copy
- Scale
- Flip
- Deinterlace
- Wide (4K) picture support
- Crop

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
[hans.verkuil@cisco.com: added missing slab.h include to bdisp-v4l2.c]

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>