Comment 1 for bug 1869123

Since there is the tag "targetmilestone-inin2004" set, I assume this bug was opened against focal / 20.04.

Doing a look-up of b59bd3527fe3 "powerpc/powernv: Return for invalid IMC domain" in the focal master tree (that correlates to the kernel that is currently in focal's release pocket and is with that the current default kernel) shows that this specific patch/commit is already in:

$ git clone https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal
...
$ git log --oneline --grep "powerpc/powernv: Return for invalid IMC domain"
b59bd3527fe3 powerpc/powernv: Return for invalid IMC domain
$ git tag --contains b59bd3527fe3
Ubuntu-5.4-5.4.0-10.13
Ubuntu-5.4-5.4.0-11.14
Ubuntu-5.4-5.4.0-12.15
Ubuntu-5.4-5.4.0-13.16
Ubuntu-5.4-5.4.0-14.17
Ubuntu-5.4.0-15.18
Ubuntu-5.4.0-16.19
Ubuntu-5.4.0-17.20
Ubuntu-5.4.0-17.21
Ubuntu-5.4.0-18.22
Ubuntu-5.4.0-19.23
Ubuntu-5.4.0-20.24
Ubuntu-5.4.0-8.11
Ubuntu-5.4.0-9.12
v5.4

So I'm wondering which kernel version was used in your case?
Please can you share the output of 'uname -a'?