Fix for Linear Advance Bug April 2nd 2023

[Zappdidappdi]

Hey,

I created a pull request with the fix of the Marlin bug.

Here is the source: https://github.com/MarlinFirmware/Marlin/compare/bugfix-2.1.x...tombrazier:Marlin:lafreeze2

This should fix issue #12 (Printer gets stuck)