media: dt-bindings: Add bindings for AKM ak7375 voice coil lens

Add device tree bindings for AKM ak7375 voice coil lens
driver. This chip is used to drive a lens in a camera module.

Signed-off-by: Tianshu Qiu <tian.shu.qiu@intel.com>
Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>