ARM: dts: emev2: update PFC node name to pin-controller

The device trees for Renesas SoCs use either pfc or pin-controller as the
node name for the PFC device. This patch is intended to take a step towards
unifying the node name used as pin-controller which appears to be the more
generic of the two and thus more in keeping with the DT specs.

My analysis is that this is a user-visible change to the extent that kernel
logs, and sysfs entries change from e0140200.pfc and pfc@e0140200 to
e0140200.pin-controller and pin-controller@e0140200.

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