Standardise and add safety comments.

These will soon be required by a lint.

Bug: 290018030
Test: m rust
Change-Id: If62281a5eb2160061a11f28588b7a14e32ce265b
diff --git a/pvmfw/avb/tests/api_test.rs b/pvmfw/avb/tests/api_test.rs
index aa9ed36..3b78663 100644
--- a/pvmfw/avb/tests/api_test.rs
+++ b/pvmfw/avb/tests/api_test.rs
@@ -244,8 +244,8 @@
     let footer = extract_avb_footer(&kernel)?;
     assert!(footer.vbmeta_offset < total_len);
     let vbmeta_offset_addr = ptr::addr_of!(footer.vbmeta_offset) as *const u8;
-    // SAFETY: It is safe as both raw pointers `vbmeta_offset_addr` and `footer` are not null.
     let vbmeta_offset_start =
+    // SAFETY: It is safe as both raw pointers `vbmeta_offset_addr` and `footer` are not null.
         unsafe { vbmeta_offset_addr.offset_from(ptr::addr_of!(footer) as *const u8) };
     let footer_start = kernel.len() - size_of::<AvbFooter>();
     let vbmeta_offset_start = footer_start + usize::try_from(vbmeta_offset_start)?;