arm64: dts: r8a7795: salvator-x: Add support for R-Car H3 ES2.0

Split off support for Salvator-X boards with the ES1.x revision of the
R-Car H3 SoC into a separate file.  The main r8a7795-salvator-x.dts file
now corresponds to Salvator-X with R-Car H3 ES2.0 or later.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>