rpmsg_sockif: add some modifaction for rpsocket

[yintao707]

Note: Please adhere to Contributing Guidelines.

Summary

1. add rpmsg_socket_ept_release for free connection
   to Fix possible use-after-free issues when closing

2. sendsize should be protected by sendlock

3. remove backlog=-1 because patch1 has removed

4. Minor cleanups
   Simplify the message process in rpmsg_socket_send_single and fix the style issue

5. use hash to handle rp_name
   expand the user's rpname size
   hash when exceed RPMSG_SOCKET_NAME_LEN due to the limitation of eptname

Impact

none

Testing

sim

[nuttxpr]

[Experimental Bot, please feedback here]

NuttX PR Requirements Review

This PR does not meet the NuttX requirements. Here's why:

• Summary:
  • The summary is too brief. It only mentions the problem ("use-after-free issues when closing") without explaining the cause or the solution.
  • It lacks details about the functional part of the code being changed.
  • It doesn't mention related issues or PRs.
• Impact:
  • While stating "none", it's unlikely a bug fix has zero impact. Be specific about what aspects remain unaffected.
• Testing:
  • Insufficient Detail: Simply stating "sim/qemu" isn't descriptive enough. Specify:
    • Host OS and versions used
    • QEMU version
    • Specific NuttX configuration for the simulation
  • Missing Logs: The "Testing logs before change" and "Testing logs after change" sections are empty. Provide concrete evidence of the issue before the fix and the successful resolution after.

To improve this PR:

1. Expand the Summary:
   • Clearly state the root cause of the use-after-free issue.
   • Describe the specific code changes made to address the problem.
   • Link any related NuttX issues this PR addresses.
2. Elaborate on Impact:
   • Even if no user-facing changes occur, explain why.
   • If internal code structure changed, mention potential future impacts.
3. Provide Detailed Testing Information:
   • List all host and target environments used for testing.
   • Include relevant snippets from logs demonstrating the issue and its resolution.

By providing a comprehensive summary, outlining the impact, and including detailed testing information, you'll make it easier for reviewers to understand and approve your PR.