media: hantro: Disable multicore support

media: hantro: Disable multicore support

Avoid exposing equal Hantro video codecs to userspace. Equal video
codecs allow scheduling work between the cores. For that kernel support
is required, which does not yet exist. Until that is implemented avoid
exposing each core separately to userspace so that multicore can be
added in the future without breaking userspace ABI.

This was written with Rockchip RK3588 in mind (which has 4 Hantro H1
cores), but applies to all SoCs.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Sebastian Fricke <sebastian.fricke@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>