acpi: pc: isa bridge: use AcpiDevAmlIf interface to build ISA device descriptors

acpi: pc: isa bridge: use AcpiDevAmlIf interface to build ISA device descriptors

replaces ad-hoc build_isa_devices_aml() with generic AcpiDevAmlIf
way to build bridge AML including all devices that are attached to
its ISA bus.

Later when PCI is converted to AcpiDevAmlIf, build_piix4_isa_bridge()
will also be dropped since PCI parts itself will take care of
building device prologue/epilogue AML for each enumerated PCI
device.

Expected AML change is contextual, where ISA devices are moved
from separately declared _SB.PCI0.ISA scope , directly under
Device(ISA) node.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Message-Id: <20220608135340.3304695-20-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>