ARM: dts: kzm9g: use generic pinctrl properties

Since 16ccaf5b

 ("pinctrl: sh-pfc: Accept standard function, pins and
groups properties") renesas pfc drivers accept generic "function", "pins"
and "groups" properties.

This patch updates the kzm9g device tree to use the generic properties.

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