media: hantro: Add support for Allwinner H6

Allwinner H6 has a Hantro G2 core used for VP9 decoding. It's not clear
at this time if HEVC is also supported or not.

Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Acked-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>