[Raspberry] `snd-bcm2835.enable_compat_alsa` is no longer defined.

[ashthespy]

@Darmur in bf30089 the kernel version based compat_alsa logic was removed.

https://github.com/volumio/volumio3-os/blob/bf30089ae6135ed7a9450ed4d77beb45a70da5e7/recipes/devices/pi.sh#L354-L355

So now an empty snd-bcm2835.enable_compat_alsa= is added to the kernel parameters (as $compat_alsa is undefined)

If this flag no longer does anything, should it also be removed to avoid confusion?

[Darmur]

yes, we should get rid of it

[foonerd]

Which init version is the target here?

[foonerd]

Tested with params and without. Alsa audio devices do not change. Please add to Bookworm.