Fixes issues with older kernels (at least <=4.19): ENOTTY for
ioctl(BLKGETZONESZ) causes `btrfs device scan` to error out and dump
users to an emergency shell during boot.
We are moving to 5.11.1 instead of reverting the 5.12.1 commit (which
would be a downgrade to 5.10), because 5.11* picked up a few bug fixes
that are nice to have.
Fixes#31275
Upstream issue: https://github.com/kdave/btrfs-progs/issues/376
Also closes#31288 by leaving a comment about the license change.
f5082ab001