Add the fixed memory type to the pci ecam driver

Add ACPI_RESOURCE_TYPE_FIXED_MEMORY32 to the PCI ECAM driver. This is
used on the Microsoft Dev Kit 2023 and reportedly the Lenovo x13s.

Reviewed by: Robert Clausecker <fuz@fuz.su> (Earlier version)
Tested by: Robert Clausecker <fuz@fuz.su> (Earlier version)
Sponsored by: Arm Ltd
Differential Revision: https://reviews.freebsd.org/D38031