vimc uses Component API to split the driver into functional components.
The real hardware resembles a monolith structure than component and
component structure added a level of complexity making it hard to
maintain without adding any real benefit.

The sensor is one vimc component that would makes sense to be a separate
module to closely align with the real hardware. It would be easier to
collapse vimc into single monolithic driver first and then split the
sensor off as a separate module.

Collapse it into a single monolithic driver removing the Component API.
This patch removes the component API and makes minimal changes to the
code base preserving the functional division of the code structure.
Preserving the functional structure allows us to split the sensor off
as a separate module in the future.

Major design elements in this change are:
- Use existing struct vimc_ent_config and struct vimc_pipeline_config
  to drive the initialization of the functional components.
- Make vimc_device and vimc_ent_config global by moving them to
  vimc-common.h
- Add two new hooks add and rm to initialize and register, unregister
  and free subdevs.
- All component API is now gone and bind and unbind hooks are modified
  to do "add" and "rm" with minimal changes to just add and rm subdevs.
- vimc-core's bind and unbind are now register and unregister.
- Add a new field to vimc_device structure for saving the pointers to
  struct vimc_ent_device(s) subdevs create in their "add" hooks. These
  get used to create links and removing the subdevs. vimc-core allocates
  this array which sized to number of entries in the topology defined in
  the vimc_pipeline_config structure.
- vimc-core invokes "add" hooks from its vimc_register_devices().
  The "add" hooks remain the same and register subdevs. They don't
  create platform devices of their own and use vimc's pdev.dev as
  their reference device. Each "add" hook returns pointer to its struct
  vimc_ent_device. This is saved in the vimc_device ent_devs array.
- vimc-core invokes "rm" hooks from its unregister to unregister subdevs
  and cleanup.
- vimc-core invokes "add" and "rm" hooks with pointer to struct vimc_device
  and the corresponding vimc_ent_device saved in the ent_devs.

The following configure and stream test works on all devices.

media-ctl -d platform:vimc -V '"Sensor A":0[fmt:SBGGR8_1X8/640x480]'
media-ctl -d platform:vimc -V '"Debayer A":0[fmt:SBGGR8_1X8/640x480]'
media-ctl -d platform:vimc -V '"Sensor B":0[fmt:SBGGR8_1X8/640x480]'
media-ctl -d platform:vimc -V '"Debayer B":0[fmt:SBGGR8_1X8/640x480]'

v4l2-ctl -z platform:vimc -d "RGB/YUV Capture" -v width=1920,height=1440
v4l2-ctl -z platform:vimc -d "Raw Capture 0" -v pixelformat=BA81
v4l2-ctl -z platform:vimc -d "Raw Capture 1" -v pixelformat=BA81

v4l2-ctl --stream-mmap --stream-count=100 -d /dev/video1
v4l2-ctl --stream-mmap --stream-count=100 -d /dev/video2
v4l2-ctl --stream-mmap --stream-count=100 -d /dev/video3
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Helen Koike <helen.koike@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>