ARM: dts: armada388-helios4: assign pinctrl to LEDs

Split up the pins to match earlier definitions. Allows LEDs to flash
properly.

Fixes: ced8025b ("ARM: dts: armada388-helios4")

Signed-off-by: Rosen Penev <rosenp@gmail.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>