The ZyXEL XGS1250-12 has a chassis fan. The fan is positioned perfectly to
provide additional cooling to the Aquantia NBase-T phys. Testing has shown
that the phys can reach temperatures upwards of 72 degrees Celsius quite
easily at about 20 degrees Celsius ambient.
Support the chassis fan to give the phys a bit of extra cooling.
Signed-off-by: Tobias Schramm <tobias@t-sys.eu>