cherry-pick fix for new amd64 ucode

cherry-pick fix for new amd64 ucode

The latest amd64-microcode package in sid [0] (which probably will
eventually make it to bookworm-security) has a change that requires
the added patch to work properly.

The changelog-entry refers to stable k.o branches only - but a quick
look through the linux-firmware.git log identifies:
`f2eb058afc57348cde66852272d6bf11da1eef8f` as relevant commit, which
refers (as NOTE in the patch) to:
a32b0f0db3f3 ("x86/microcode/AMD: Load late on both threads too")
which applies cleanly (although I cherry-picked the patch from the
6.1.y stable branch to have the original commit in the commit
message).

quickly tested compiling and booting the result in a VM (however w/o
a fitting CPU (Epyc Genoa or Bergamo) it should cause a change)

reported in our Enterprise Support as potential culprit for one
thread from 128 being reported as offline in `lscpu`

[0] https://metadata.ftp-master.debian.org/changelogs//non-free-firmware/a/amd64-microcode/amd64-microcode_3.20230808.1.1_changelog

Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>