x86: Increase remapping region size

If we have to map the MMCONFIG space of a complete PCI section, we run
out of remapping space. 4 means 128K pages, more than enough for now.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
configs: Enable MMCONFIG moderation for QEMU Q35 and H87i

Exclude the MMCONFIG regions from memory regions so that Jailhouse can
intercept accesses. Not yet converted is the H700 config.

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

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