files: make uart_bus_puc.c not depend on puc

[manu]

Summary

If one wants to have puc working as a module we need the bus
in the kernel otherwise we won't be able to find any child to attach.

Sponsored by: Beckhoff Automation GmbH & Co. KG

Test Plan

Remove puc from kernel config, loading puc (manually or via devmatch or loader) and uart devices are created correctly.

[manu]

I've tried to make a puc_bus module that contain dev/uart/uart_bus_puc.c and make puc depends on this, but behavior is the same.

[imp]

This change is correct. It should be made no matter what. Puc is tied to pci.
I also think it shows some weaknesses in how we build ko.
What's your bigger picture goal in wanting to make puc more of a first class bus or module?

[manu]

In D43846#1000175, @imp wrote:

This change is correct. It should be made no matter what. Puc is tied to pci.

Thanks, I wasn't sure that this was the correct change or more an hack :)

I also think it shows some weaknesses in how we build ko.
What's your bigger picture goal in wanting to make puc more of a first class bus or module?

We have puc(4) device at work and most of our customer wants to use the uart for our PLC stuff so our kernel config doesn't include it.
But some customer wants it for connecting to devices via FreeBSD.
So with this change we have what we want :)