media: ov2680: Drop unnecessary pad checks

Drop unnecessary pad checks in enum_mbus_code, get_fmt, set_fmt
this is already checked by check_pad() from
drivers/media/v4l2-core/v4l2-subdev.c.

Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>