media: platform: meson-ao-cec-g12a: add support for SM1

Add support for the Amlogic SM1 SoC Family to the G12A AO-CECB
derivative.

It only adds a single init register.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
[hverkuil-cisco@xs4all.nl: dropped spurious newline]
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>