sparc: add kernel debug output

Mostly the same as PowerPC, using OpenFirmware.

Change-Id: I197cc181e92da92c272ee9cfa20c8ad2d2c63d41
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3579
Reviewed-by: waddlesplash <waddlesplash@gmail.com>

sparc: pci bus manager

Copied from PPC with the hooks for Apple hardware removed.
To be completed with the actual PCI bus implementation for Sun machines.
This is where we start doing machine specific stuff, apparently.

Change-Id: I06af4de9621e9d40593d153642478d928083e49a
Reviewed-on: https://review.haiku-os.org/c/1364
Reviewed-by: waddlesplash <waddlesplash@gmail.com>