arm: remove up_set_current_regs/up_current_regs

[hujun260]

Summary

remove up_set_current_regs/up_current_regs
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Currently, we record the context in other ways, so the second function is obsolete.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

arm arch

Testing

ostest
qemu
qemu-armv7a:smp
mps2-an500:nsh

[nuttxpr]

[Experimental Bot, please feedback here]

Yes, this PR appears to meet the basic NuttX requirements, although some sections could be more thoroughly filled out. Specifically:

• Summary: While the reasoning is provided, a clear statement of what up_set_current_regs is being renamed to is missing. This is crucial information.
• Impact: While "arm arch" is mentioned, this needs to be more specific. Which ARM architectures? Are all ARM architectures affected? Also, explicitly answer the provided impact questions (user, build, hardware, documentation, security, compatibility). Even if the answer is "NO", stating it explicitly avoids ambiguity. For example, will this change require any documentation updates?
• Testing: While target platforms are listed, the "Build Host(s)" information is missing. Also, the "Testing logs before change" and "Testing logs after change" sections are empty. These sections are crucial for demonstrating that the change works as intended and doesn't introduce regressions. Include actual log output, even if it's just a simple "ostest passed" message.

Recommendation: Revise the PR description to address the missing information highlighted above. A more complete description will make it easier for reviewers to understand and approve the changes.

[pussuw]

Update the comment (current_regs is wrong). See if current_regs is mentioned elsewhere too?

[hujun260]

ok