Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging

* More uses of RCU_READ_LOCK_GUARD (Dave, myself)
* QOM doc improvments (Greg)
* Cleanups from the Meson conversion (Marc-André)
* Support for multiple -accel options (myself)
* Many x86 machine cleanup (Philippe, myself)
* tests/migration-test cleanup (Juan)
* PC machine removal and next round of deprecation (Thomas)
* kernel-doc integration (Peter, myself)

# gpg: Signature made Wed 18 Dec 2019 01:35:02 GMT
# gpg:                using RSA key BFFBD25F78C7AE83
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>" [full]
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>" [full]
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4  E2F7 7E15 100C CD36 69B1
#      Subkey fingerprint: F133 3857 4B66 2389 866C  7682 BFFB D25F 78C7 AE83

* remotes/bonzini/tags/for-upstream: (87 commits)
  vga: cleanup mapping of VRAM for non-PCI VGA
  hw/display: Remove "rombar" hack from vga-pci and vmware_vga
  hw/pci: Remove the "command_serr_enable" property
  hw/audio: Remove the "use_broken_id" hack from the AC97 device
  hw/i386: Remove the deprecated machines 0.12 up to 0.15
  hw/pci-host: Add Kconfig entry to select the IGD Passthrough Host Bridge
  hw/pci-host/i440fx: Extract the IGD passthrough host bridge device
  hw/pci-host/i440fx: Use definitions instead of magic values
  hw/pci-host/i440fx: Use size_t to iterate over ARRAY_SIZE()
  hw/pci-host/i440fx: Extract PCII440FXState to "hw/pci-host/i440fx.h"
  hw/pci-host/i440fx: Correct the header description
  Fix some comment spelling errors.
  target/i386: remove unused pci-assign codes
  WHPX: refactor load library
  migration: check length directly to make sure the range is aligned
  memory: include MemoryListener documentation and some missing function parameters
  docs: add memory API reference
  memory.h: Silence kernel-doc complaints
  docs: Create bitops.rst as example of kernel-docs
  bitops.h: Silence kernel-doc complaints
  ...

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