configs: Add Q35 machine support to QEMU VM

Add required PCI devices to the QEMU config so that it both works with
the default i440FX and the newer Q35 machine. This is transitional until
Q35 gains VT-d support, then we will drop i440FX bits.

Open the whole 0xC0xx port range for PCI devices to be more tolerant
regarding ordering or other changes.

At this chance, drop the unneeded permission to talk to the first legacy
PIC.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Update TODO list

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
configs: Drop Celsius W420

No machine of this type in reach, so we cannot update to recent config
extensions. Also, we will soon focus on auto-generated configs.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>