media: i2c: ov6650: Drop implementation of .set_mbus_config()

The subdev .set_mbus_config() operation is deprecated. No code in the
kernel calls it, so drop its implementation from the ov6650 driver.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>