media: atomisp: ov2680: Drop MAX_FMTS define

The ov2680 only supports a single format, there is no need to
use a define for this.

Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>