drm: renesas: shmobile: Add DT support

Add DT support, by:
1. Creating a panel bridge from DT, and attaching it to the encoder,
2. Replacing the custom connector with a bridge connector,
3. Obtaining clock configuration based on the compatible value.

Note that for now the driver uses a fixed clock configuration selecting
the bus clock, as the current code to select other clock inputs needs
changes to support any other SoCs than SH7724.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/6185ab76aa300fa402e4f6610b2109665f2d8a1c.1694767209.git.geert+renesas@glider.be

drm: renesas: shmobile: Move interface handling to connector setup

Move legacy interface handling to the connector setup code.
Set up bus_flags and bus_formats in display_info according to the
bus format and panel information from platform data, to make it more
similar with DT-based connector/bridge/panel setup.
This will allow us to use the same LCD interface setup code for both
legacy and DT-based systems.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/912f615eb87c847804a268200ab57c63453c65d4.1694767209.git.geert+renesas@glider.be

drm: renesas: shmobile: Replace .dev_private with container_of()

Now that drm_device is embedded in shmob_drm_device, we can use
a container_of()-based helper to get the shmob_drm_device pointer from
the drm_device, instead of using the deprecated drm_device.dev_private
field.

While at it, restore reverse Xmas tree ordering of local variable
declarations.

Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Sui Jingfeng <suijingfeng@loongson.cn>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/8ef4be8bffe75efc7f4b66f3732ec357f7d43e0f.1694767209.git.geert+renesas@glider.be

drm: renesas: shmobile: Embed drm_device in shmob_drm_device

Embedding drm_device in shmob_drm_device allows us to use the DRM
managed API to allocate both structures in one go, simplifying error
handling.

Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/abbf95021191824f44cc8c52e4afbde93d44363a.1694767209.git.geert+renesas@glider.be

drm: renesas: shmobile: Remove backlight support

Backlight support should be implemented by panels, not by the LCDC
driver. As the feature is currently unused anyway, remove it.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
[geert: Cleanups]
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/69707650245bc2193d072f24723d4d5482ea590b.1694767209.git.geert+renesas@glider.be

drm: Place Renesas drivers in a separate dir

Create vendor specific renesas directory and move renesas drivers
to that directory.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Acked-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>