virtio, vhost, acpi: features, fixes, tests

ARM ACPI memory hotplug support +
tests for new arm/virt ACPI tables.

Virtio fs support (no migration).
A vhost-user reconnect bugfix.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

# gpg: Signature made Tue 15 Oct 2019 22:02:19 BST
# gpg:                using RSA key 281F0DB8D28D5469
# gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>" [full]
# gpg:                 aka "Michael S. Tsirkin <mst@redhat.com>" [full]
# Primary key fingerprint: 0270 606B 6F3C DF3D 0B17  0970 C350 3912 AFBE 8E67
#      Subkey fingerprint: 5D09 FD08 71C8 F85B 94CA  8A0D 281F 0DB8 D28D 5469

* remotes/mst/tags/for_upstream:
  virtio: add vhost-user-fs-pci device
  virtio: add vhost-user-fs base device
  virtio: Add virtio_fs linux headers
  tests/acpi: add expected tables for arm/virt
  tests: document how to update acpi tables
  tests: Add bios tests to arm/virt
  tests: allow empty expected files
  tests/acpi: add empty files
  tests: Update ACPI tables list for upcoming arm/virt tests
  docs/specs: Add ACPI GED documentation
  hw/arm: Use GED for system_powerdown event
  hw/arm: Factor out powerdown notifier from GPIO
  hw/arm/virt-acpi-build: Add PC-DIMM in SRAT
  hw/arm/virt: Enable device memory cold/hot plug with ACPI boot
  hw/arm/virt: Add memory hotplug framework
  hw/acpi: Add ACPI Generic Event Device Support
  hw/acpi: Do not create memory hotplug method when handler is not defined
  hw/acpi: Make ACPI IO address space configurable
  vhost-user: save features if the char dev is closed

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>