media: i2c: Drop unused vs6624 camera sensor driver

The vs6624 camera sensor driver doesn't support DT and relies on
platform data. The last board files supplying platform data for that
device have been removed from the kernel in v4.17. The driver hasn't
been used since them. Drop it.

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