MFC r340595-r340597

r340595:
pci_host_generic: remove unneeded ThunderX2 quirk

The current quirk implementation writes a fixed address to the PCI BAR
to fix a firmware bug. The PCI BARs are allocated by firmware and will
change depending on PCI devices present. So using a fixed address here
is not correct.

This quirk worked around a firmware bug that programmed the MSI-X bar
of the SATA controller incorrectly. The newer firmware does not have
this issue, so it is better to drop this quirk altogether.

Reviewed by: andrew
Differential Revision: https://reviews.freebsd.org/D17655

r340596:
pci_host_generic: allocate resources against devices

Fix up pci_host_generic.c and pci_host_generic_fdt.c to allocate
resources against devices that requested them. Currently the
allocation happens against the pcib, which is incorrect.

This is needed for the upcoming changes for fixing up
pci_host_generic_acpi.c

Reviewed by: andrew
Differential Revision: https://reviews.freebsd.org/D17656

r340597:
pci_host_generic*: basic implementation of bus range

Both ACPI and FDT support bus ranges for pci host bridges. Update
pci_host_generic*.[ch] with a default implementation to support this.
This will be used in the next set of changes for ACPI based host
bridge. No functional changes in this commit.

Reviewed by: andrew
Differential Revision: https://reviews.freebsd.org/D17657