The PFTF CM4 is an ACPI platform that isn't ECAM compliant. Its config
space is in two parts. One part is for the root port registers and a
second moveable window pointing at a device's 4K config space. Thus it
doesn't have an MCFG, and any MCFG provided would be nonsense
anyway. Instead, a Linux specific host bridge _DSD selects a custom
ECAM ops and cfgres. The cfg op picks between those two regions while
disallowing problematic accesses.
Signed-off-by: Jeremy Linton <jeremy.linton@xxxxxxx>