media: imx: Rename imx7-mipi-csis.c to imx-mipi-csis.c

Rename the imx7-mipi-csis.c driver to remove the reference to i.MX7.

The driver is for an IP core found on i.MX7 and i.MX8 SoC, so do not
specify a SoC version number in the driver name.

Remove the references to the i.MX7 SoC in the driver symbols and expand
the driver's header with more information about the IP core the driver
controls.

Also rename the associated bindings documentation.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: imx7.rst: Provide an example for imx6ull-evk capture

imx6ull-evk has a parallel OV5640 sensor.

Provide an example for imx6ull-evk capture to improve the document.

Signed-off-by: Fabio Estevam <festevam@denx.de>
Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: docs: move user-facing docs to the admin guide

Most of the driver-specific documentation is meant to help
users of the media subsystem.

Move them to the admin-guide.

It should be noticed, however, that several of those files
are outdated and will require further work in order to make
them useful again.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>