rpi4: snd_bcm2835 kernel module not being loaded on newer balenaOS versions

[tmigone]

Latest balenaOS versions don't load the snd_bcm2835 driver by default. This results in the following problems:

• [ ] Audio jack not working (no driver)
• [ ] HDMI audio drivers not being picked up by the audio block

Investigating the exact balenaOS version where this broke and the solution.

Working on replicating this issue so far with no success.