The RPi4 WiFi chip and HDMI outputs have some frequency overlap with
crosstalk around 2.4GHz. Let's mark it as such so we can use some evasive
maneuvers.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20201029134018.1948636-3-maxime@cerno.tech