arm64: dts: renesas: Consolidate Salvator-X(S) HDMI0 handling

Now all Salvator-X(S) SoC/board combinations have support for HDMI
sound, all HDMI0 connector and sound descriptions are identical.
Replace them by shared descriptions in salvator-common.dtsi, to reduce
duplication.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/20210303140529.3941670-1-geert+renesas@glider.be

arm64: dts: renesas: r8a77965-salvator-x(s): Enable HDMI sound

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: Jacopo Mondi <jacopo+renesas@jmondi.org> # Salvator-XS
[geert: Preserve sort order]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

arm64: dts: renesas: r8a77965-salvator-x: Enable DU external clocks and HDMI

The DU1 external dot clock is provided by the fixed frequency clock
generator X21, while the DU0 and DU3 clocks are provided by the
programmable Versaclock5 clock generator.

Enable the clocks, and the HDMI encoder for the M3-N Salvator-X board
and hook it up to the HDMI connector.

Based on patches from Takeshi Kihara <takeshi.kihara.df@renesas.com>

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arm64: dts: renesas: Add R-Car Salvator-x M3-N support

Add basic support for R-Car Salvator-X M3-N (R8A77965) board.

Based on original work from:
Takeshi Kihara <takeshi.kihara.df@renesas.com>
Magnus Damm <damm+renesas@opensource.se>

Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>