arm64: dts: renesas: rcar: Rename dsi-encoder to dsi

arm64: dts: renesas: rcar: Rename dsi-encoder to dsi

Rename "dsi-encoder" nodes to "dsi" to follow node name pattern in
Documentation/devicetree/bindings/display/dsi-controller.yaml.
No functional change.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20250904210147.186728-1-marek.vasut+renesas@mailbox.org
Link: https://patch.msgid.link/20250904210147.186728-2-marek.vasut+renesas@mailbox.org
Link: https://patch.msgid.link/20250904210147.186728-3-marek.vasut+renesas@mailbox.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>