We have appropriate versions of our DUART28C support patches that apply cleanly
to every mainline kernel version since 5.10.  The correspondence table of which
FC patch version should be used with which mainline kernel version is:

Mainline kernel version range	Use FC patch version based on
-------------------------------------------------------------
5.10 and 5.11			5.10
5.12 through 6.0		5.12
6.1 through 6.7			6.1