media: dt-bindings: media: i2c: Rename ov5647.yaml

Rename 'ov5647.yaml' as 'ovti,ov5647.yaml' and update the
MAINTAINERS file entry accordingly.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>