media: meson: add v4l2 m2m video decoder driver

Amlogic SoCs feature a powerful video decoder unit able to
decode many formats, with a performance of usually up to 4k60.

This is a driver for this IP that is based around the v4l2 m2m framework.

It features decoding for:
- MPEG 1
- MPEG 2

Supported SoCs are: GXBB (S905), GXL (S905X/W/D), GXM (S912)

There is also a hardware bitstream parser (ESPARSER) that is handled here.

Signed-off-by: Maxime Jourdan <mjourdan@baylibre.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>