ARM: dts: renesas: Fix pin controller node names

According to Devicetree Specification v0.2 and later, Section "Generic
Names Recommendation", the node name for a pin controller device node
should be "pinctrl".

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/20200821112351.5518-1-geert+renesas@glider.be