acpi: pc: add fw_cfg device node to dsdt

acpi: pc: add fw_cfg device node to dsdt

Add a fw_cfg device node to the ACPI DSDT. While the guest-side
firmware can't utilize this information (since it has to access
the hard-coded fw_cfg device to extract ACPI tables to begin with),
having fw_cfg listed in ACPI will help the guest kernel keep a more
accurate inventory of in-use IO port regions.

Signed-off-by: Gabriel Somlo <[email protected]>
Reviewed-by: Laszlo Ersek <[email protected]>
Reviewed-by: Marc Marí <[email protected]>
Reviewed-by: Michael S. Tsirkin <[email protected]>
Message-id: 1455906029[email protected]
Signed-off-by: Gerd Hoffmann <[email protected]>