Merge tag 'nvme-next-pull-request' of git://git.infradead.org/qemu-nvme into staging

hw/nvme updates

performance improvements by Jinhao
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* shadow doorbells
* ioeventfd

plus some misc fixes (Darren, Niklas).

# gpg: Signature made Fri 15 Jul 2022 09:42:20 BST
# gpg:                using RSA key 522833AA75E2DCE6A24766C04DE1AF316D4F0DE9
# gpg: Good signature from "Klaus Jensen <its@irrelevant.dk>" [unknown]
# gpg:                 aka "Klaus Jensen <k.jensen@samsung.com>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: DDCA 4D9C 9EF9 31CC 3468  4272 63D5 6FC5 E55D A838
#      Subkey fingerprint: 5228 33AA 75E2 DCE6 A247  66C0 4DE1 AF31 6D4F 0DE9

* tag 'nvme-next-pull-request' of git://git.infradead.org/qemu-nvme:
  hw/nvme: Use ioeventfd to handle doorbell updates
  nvme: Fix misleading macro when mixed with ternary operator
  hw/nvme: force nvme-ns param 'shared' to false if no nvme-subsys node
  hw/nvme: fix example serial in documentation
  hw/nvme: Add trace events for shadow doorbell buffer
  hw/nvme: Implement shadow doorbell buffer support

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