media: atomisp: report colorspace information

While different sensors could have different colorspaces, the
colorspace V4L2 support didn't exist by the time atomisp driver
was written. So, the sensors won't have any data about that.

So, let's report what Asus T101HA uses (ov2680 sensor).

It may require further changes, if other sensors used on this
driver have different colorspaces.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>