media: ov5693: Convert to new CCI register access helpers

Use the new comon CCI register access helpers to replace the private
register access helpers in the ov5693 driver.

[Sakari Ailus: Squashed the patch to address a merge issue in Kconfig]

Reviewed-by: Laurent Pinchart <laurent.pinchart@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>