Rpmsg ping: improve the rpmsg ping

[CV-Bowen]

Summary

• rpmsg_ping.c: fix msg data memset length

The range of memset exceeds the size of the buffer

• rpmsg_ping.c: change msg cmd type for more compatible

Use bit mask method to represent the command, because it's more
convenient to express multiple characteristics simultaneously.

• rpmsg_ping.c: improve log level to LOG_EMERG

Usually rpmsg ping logs are needed during testing,
but too many other module logs can easily overwrite it,
so improve the rpmsg ping log level, later we can setlogmask to
a higher log level to mask other modules' logs.

• rpmsg_ping.c: change check data to fluctuation value

We can found the error happend packet more accurately based
on the data value.

Impact

rpmsg ping

Testing

sim:rpserver and rpproxy

[nuttxpr]

[Experimental Bot, please feedback here]

This pull request appears to meet the NuttX requirements. Here's a breakdown:

Meets Requirements:

• Summary: Clearly describes the "why" and "what" of each change. References to related issues would strengthen it further.
• Impact:
  • Specifies that changes affect the rpmsg_ping functionality.
  • While it implies "NO" for most impact categories, explicitly stating it would improve clarity.
• Testing:
  • Indicates testing environments (sim:rpserver and rpproxy).
  • Providing actual testing logs, even if brief, would significantly strengthen the PR.

Recommendations for Improvement:

• Summary: Add links to related NuttX issues if they exist.
• Impact: Be explicit about the impact categories (e.g., "Impact on build: NO").
• Testing: Include snippets of actual testing logs before and after the changes. This provides concrete evidence that the changes work as intended.

Overall: The PR provides a good starting point. Adding the recommended details will make it even stronger and easier for reviewers to assess.

[CV-Bowen]

Need merge with PR: apache/nuttx-apps#2677