Bugfix/fix esp spi slave receive data

[FelipeMdeO]

Note: Please adhere to Contributing Guidelines.

Summary

This PR fix know issue in esp32c6 spi slave driver. The issue was presented here: #13238

Also, this PR add spi slave configuration to esp32c6 devkitm

Impact

Now esp32c6 can get data received from spi master properly.

Testing

2 esp32c6 devikit m were used, one as master and other as slave. In image below you will see tests. In the right side master sends data to slave and in the left side slave, running a simple application, can read exactly data sent by master.

Tnx @Donny9 for improve and fix issues in top half layer.

[nuttxpr]

[Experimental Bot, please feedback here]

Fill In The Commit Message: This PR contains a Commit with an Empty Commit Message. Please fill in the Commit Message with the PR Summary.

The provided PR information seems to meet most of the NuttX requirements. However, it would benefit from slight improvements for better clarity and completeness.

Strengths:

• Clear Summary: The summary explains the "why" (fixing a known issue), the "what" (fixing the esp32c6 SPI slave driver and adding configuration), and links the relevant issue.
• Impact Description: It highlights the positive impact on functionality (esp32c6 can now receive data properly).
• Testing Evidence: It mentions the testing setup (two esp32c6 devkit m boards) and provides visual proof of successful communication between master and slave.

Areas for Improvement:

• Impact - Be More Specific:
  • While stating that "esp32c6 can now get data received properly" is good, elaborate on the impact in a bit more detail. For example:
    • "Previously, the esp32c6 SPI slave driver had an issue where [describe the exact issue - e.g., data was not being received consistently, there were errors, etc.]. This fix resolves this issue, enabling reliable SPI slave communication on the esp32c6."
  • Go through each impact category (build, hardware, documentation, security, compatibility) and explicitly state "NO" or provide a brief explanation if applicable.
• Testing - Add Logs (If Possible):
  • While the image is helpful, consider including relevant code snippets or logs from both master and slave devices to demonstrate the data exchange. This provides more concrete evidence of the fix. If logs are too long, consider adding them as a separate file in the PR.

Example of Improved Impact Section:

## Impact

* **Is new feature added?** NO
* **Is existing feature changed?** YES, the esp32c6 SPI slave driver is fixed.
* **Impact on user:** YES, users can now reliably use the esp32c6 as an SPI slave device.  Prior to this fix, the driver had issues with [describe the specific issue], preventing proper data reception.
* **Impact on build:** NO
* **Impact on hardware:** NO 
* **Impact on documentation:**  YES, the esp32c6 devkitm configuration now includes SPI slave settings, requiring documentation updates to reflect this.
* **Impact on security:** NO
* **Impact on compatibility:** NO
* **Anything else to consider:**  N/A

By making these improvements, the PR will be more comprehensive, informative, and easier for reviewers to assess.