media: dt-bindings: Add OV5642

As explained in the description text from trivial-devices.yaml:

"This is a list of trivial I2C and SPI devices that have simple device tree
bindings, consisting only of a compatible field, an address and possibly an
interrupt line."

A camera device does not fall into this category as it needs other
properties such as regulators, reset and powerdown GPIOs, clocks,
media endpoint.

Remove the OV5642 entry from trivial-devices.yaml and add its own
ovti,ov5642.yaml.

Signed-off-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>