[bootlin/training-materials] 002432: sysdev: labs: update Linux stable git URL

[Luca Ceresoli]

  Branch: refs/heads/master
  Home:   https://github.com/bootlin/training-materials
  Commit: 00243239a94ad377be9d8f17257dc8643e8aaf43
      https://github.com/bootlin/training-materials/commit/00243239a94ad377be9d8f17257dc8643e8aaf43
  Author: Luca Ceresoli <luca.ceresoli at bootlin.com>
  Date:   2022-12-07 (Wed, 07 Dec 2022)

  Changed paths:
    M common/kernel-clone-master-and-stable.tex

  Log Message:
  -----------
  sysdev: labs: update Linux stable git URL

The official path according to git.kernel.org ends with '/linux', not
'/linux-stable' even though the latter still works. We have the correct one
in the slides, fix the labs.

Signed-off-by: Luca Ceresoli <luca.ceresoli at bootlin.com>