pthread: remove enter_critical_section in pthread_mutex

[hujun260]

Summary

pthread: remove enter_critical_section in pthread_mutex

reason:
We would like to replace the critical section with a small lock.

Impact

pthread

Testing

ci ostest

[nuttxpr]

[Experimental Bot, please feedback here]

No, this PR does not fully meet the NuttX requirements. While it provides a reason for the change and identifies a related PR, it lacks crucial information.

Here's what's missing:

• Insufficient Summary: The summary needs to be more detailed. It should explain how the change works (the mechanism of replacing the critical section) and what functional part of the code is affected beyond just "pthread."
• Missing Impact Details: Simply stating "pthread" is not enough. The impact section requires YES/NO answers for all listed items (user impact, build impact, hardware impact, documentation, security, compatibility). If any answer is YES, a description is mandatory. For example, even if the answer to "Impact on user" is NO, you should still explicitly state "NO".
• Inadequate Testing Information: "ci ostest" is insufficient. The requirements ask for:
  • Specific build host details (OS, CPU, compiler version).
  • Specific target details (architecture, board, configuration).
  • Actual testing logs before and after the change, not just a reference to CI. While CI is important, the PR should demonstrate local verification.

Therefore, the PR needs substantial revision to meet the stated requirements before it can be properly reviewed.