Enable CM4 external antenna

[andypiper]

The CM4 has a wireless chip with internal antenna, plus a U.FL connector for an external antenna. The CM4 core carrier board comes with an external antenna to connect to the U.FL connector on the CM4 👍🏻

The current v0.1 image for the CM4 board (64-bit) does not enable the external antenna.

It's an easy fix. In /boot/config.txt set

dtparam=ant2

Source information here