arm64: dts: mt6358: change node names

- Change the node name from "mt6358" to "pmic", "mt6358rtc" to "rtc" and
"mt6358keys" to "keys" to be consistent with the generic names recommendation.

Signed-off-by: Alexandre Mergnat <amergnat@baylibre.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20221005-mt6357-support-v8-4-560caaafee53@baylibre.com


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>