Claude review: arch: use rest_of_page() macro where appropriate

[Claude Code Review Bot <claude-review@example.com>]

Patch Review

- `arch/arm64/kernel/patching.c`: Correct replacement. **Minor nit:** a blank line between the `size = ...` assignment and `waddr = patch_map(...)` was removed. This is an unrelated whitespace change.
  ```c
  -		size = min_t(size_t, PAGE_SIZE - offset_in_page(ptr),
  -			     len - patched);
  -
  +		size = min_t(size_t, rest_of_page(ptr), len - patched);
   		waddr = patch_map(ptr, FIX_TEXT_POKE0);
  ```
  The original had a visual separator; removing it is a style change that should be separate or at least mentioned.

- `arch/powerpc/lib/code-patching.c`: Two comment updates and one code change. The comment updates replacing `(PAGE_SIZE - offset_in_page(addr))` with `rest_of_page(addr)` in the function documentation are a nice touch. Code change is correct.

- `arch/riscv/kernel/sbi.c`: Two replacements in `sbi_debug_console_write()` and `sbi_debug_console_read()`. Correct — the guard condition `PAGE_SIZE < (offset_in_page(bytes) + num_bytes)` ensures we only reach the assignment when `rest_of_page(bytes) < num_bytes`.

---
Generated by Claude Code Patch Reviewer