stm32l4x6: Enable watchdog independently of NDEBUG

[anglov]

JIRA: DEND-32

Description

Motivation and Context

Provide a possibility to enable/disable watchdog without BOARD_CONFIG env

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

How Has This Been Tested?

• Already covered by automatic testing.
• New test added: (add PR link here).
• Tested by hand on: (list targets here).

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing linter checks and tests passed.
• My changes generate no new compilation warnings for any of the targets.

Special treatment

• This PR needs additional PRs to work (list the PRs, preferably in merge-order).
  _projects: disable WATCHDOG in projects phoenix-rtos-project#847
  stm32l4x6: Enable watchdog independently of NDEBUG #293
  Watchdog changes phoenix-rtos-kernel#453
  make: Add passing WATCHDOG as define phoenix-rtos-build#163
• I will merge this PR by myself when appropriate.

[github-actions]

Unit Test Results

5 721 tests   5 076 ✔️  25m 13s ⏱️
   290 suites     645 💤
       1 files           0 ❌

Results for commit 7905617.

♻️ This comment has been updated with latest results.