rp23xx_irq.c: fix regression from https://github.com/apache/nuttx/pull/15073

[hujun260]

Summary

fix regression from #15073

Impact

arch/arm/src/rp23xx/rp23xx_irq.c

Testing

ci #15503

[nuttxpr]

[Experimental Bot, please feedback here]

No. This PR description lacks crucial information required by the NuttX guidelines.

Here's what's missing:

• Summary: While it links a prior PR, it doesn't explain what the regression is. What functionality was broken? How does this PR fix it? What part of the code was changed and how?
• Impact: The current entry just lists a file path. It needs to explicitly answer all the impact questions (user impact, build impact, hardware impact, documentation, security, compatibility). Use "NO" or "YES" followed by a description if yes.
• Testing: Linking to a CI issue isn't sufficient. It needs to specify the local test setup used (host OS, compiler, target architecture and board) and provide actual before/after testing logs demonstrating the fix. Simply pointing to a CI run doesn't show what specific tests were run locally and their results.

The author needs to substantially expand this PR description to be accepted.