ARM: dts: bcm2711-rpi-4-b: Add SoC GPIO labels

This adds the labels for all the SoC GPIOs on the Raspberry Pi 4.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/1581166975-22949-5-git-send-email-stefan.wahren@i2se.com


Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>