acpi: arm: add fw_cfg device node to dsdt

acpi: arm: add fw_cfg device node to dsdt

Add a fw_cfg device node to the ACPI DSDT. This is mostly
informational, as the authoritative fw_cfg MMIO region(s)
are listed in the Device Tree. However, since we are building
ACPI tables, we might as well be thorough while at it...

Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Marc Marí <markmb@redhat.com>
Reviewed-by: Shannon Zhao <shannon.zhao@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 1455906029-25565-5-git-send-email-somlo@cmu.edu
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>