Merge remote-tracking branch 'remotes/nvme/tags/nvme-fixes-pull-request' into staging

Two small fixes for regressions reported by Alexander Graf and Bin Meng.

v2: spotted one bug in the error handling.

# gpg: Signature made Thu 11 Feb 2021 15:19:30 GMT
# gpg:                using RSA key 522833AA75E2DCE6A24766C04DE1AF316D4F0DE9
# gpg: Good signature from "Klaus Jensen <[email protected]>" [unknown]
# gpg:                 aka "Klaus Jensen <[email protected]>" [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

* remotes/nvme/tags/nvme-fixes-pull-request:
  hw/block/nvme: fix error handling in nvme_ns_realize
  hw/block/nvme: Fix a build error in nvme_get_feature()
  hw/block/nvme: fix legacy namespace registration

Signed-off-by: Peter Maydell <[email protected]>