ARM: dts: bcm2711-rpi-400: Fix GPIO line names

The GPIO expander line names has been fixed in the vendor tree last year,
so upstream these changes.

Fixes: 1c701acc ("ARM: dts: Add Raspberry Pi 400 support")
Reported-by: Ivan T. Ivanov <iivanov@suse.de>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>