Merge tag 'migration-20240322-pull-request' of https://gitlab.com/peterx/qemu into staging

Migration pull for 9.0-rc1

- Fabiano's patch to revert fd: support on mapped-ram
- Peter's fix on postcopy regression on unnecessary dirty syncs
- Fabiano's fix on mapped-ram rare corrupt on zero page handling

# -----BEGIN PGP SIGNATURE-----
#
# iIgEABYKADAWIQS5GE3CDMRX2s990ak7X8zN86vXBgUCZf2uIxIccGV0ZXJ4QHJl
# ZGhhdC5jb20ACgkQO1/MzfOr1waqTgD/RjaWrcUYlHcfFcWlEQGrYqikCtZYI+oW
# YYdbLcCBOlQBAL/ecCbsFyaWyPnB1Eg3YFcj5g8AgogDHdg37HSxydgL
# =aWGi
# -----END PGP SIGNATURE-----
# gpg: Signature made Fri 22 Mar 2024 16:13:23 GMT
# gpg:                using EDDSA key B9184DC20CC457DACF7DD1A93B5FCCCDF3ABD706
# gpg:                issuer "peterx@redhat.com"
# gpg: Good signature from "Peter Xu <xzpeter@gmail.com>" [marginal]
# gpg:                 aka "Peter Xu <peterx@redhat.com>" [marginal]
# gpg: WARNING: This key is not certified with sufficiently trusted signatures!
# gpg:          It is not certain that the signature belongs to the owner.
# Primary key fingerprint: B918 4DC2 0CC4 57DA CF7D  D1A9 3B5F CCCD F3AB D706

* tag 'migration-20240322-pull-request' of https://gitlab.com/peterx/qemu:
  migration/multifd: Fix clearing of mapped-ram zero pages
  migration/postcopy: Fix high frequency sync
  migration: Revert mapped-ram multifd support to fd: URI

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