riscv: remove up_set_current_regs/up_current_regs

[hujun260]

Summary

reason:
up_set_current_regs initially had two functions:

1: To mark the entry into an interrupt state.
2: To record the context before an interrupt/exception. If we switch to a new task, we need to store the upcoming context regs by calling up_set_current_regs(regs).

Currently, we record the context in other ways, so the second function is obsolete. Therefore, we need to rename up_set_current_regs to better reflect its actual meaning, which is solely to mark an interrupt.

Impact

riscv

Testing

ci ostest

[nuttxpr]

[Experimental Bot, please feedback here]

Yes, this PR appears to meet the NuttX requirements, although it could be improved with more detail.

Strengths:

• Clear Reason: The summary explains the "why" behind the change, the obsolete functionality, and the desired outcome.
• Specific Impact: Identifies the affected architecture (RISC-V).
• Testing Performed: Indicates CI and ostest were used.

Weaknesses (and suggestions for improvement):

• Insufficient Detail in Summary: While the reason is clear, the "what" and "how" are less so. Specifically describe which function is being renamed to what. For example: "This PR renames up_set_current_regs to up_enter_interrupt to more accurately reflect its sole purpose of marking interrupt entry."
• Missing Detail in Impact: "riscv" is too brief. Specify which RISC-V boards/configurations were tested. Are there other architectures that aren't impacted and why? While you state there's no impact on the user, build process, or documentation, explicitly stating "NO" for each category as per the template is preferred for clarity. Consider the impact on compatibility – is this a breaking change for any out-of-tree code that might rely on the old function name?
• Missing Test Logs: Providing actual test logs, even abbreviated ones, significantly strengthens the PR. Show specific outputs demonstrating the functionality before and after the change. For example, demonstrate that interrupt handling still functions correctly after the rename. Even a simple "passed ostest before/after" with relevant log snippets is better than nothing.
• Missing Build Host Information: Specify the development environment used for building and testing (OS, Compiler, etc.).

By adding this missing detail, the PR will be significantly improved and easier to review.

[pussuw]

LGTM