media: dt-bindings: media: add microchip,xisc device bindings

Add bindings for the Microchip eXtended Image Sensor Controller.
Based on the atmel,isc.yaml binding.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>