lapd: The two known LAPDm issues have been addressed, update the test

The issue about the wrong padding has been found when creating the
testcase in commit 15f740caa3a1ef681b3a5564daf6dfccb7b1e489 but the
patch to fix that was never proposed by inclusion by its author.

The issue about about the establish confirm carrying data with
a wrong size is still present.
2 files changed