lib: add explanation comment in "work->handler" case

Coding scanning tool raises a violation that happens dereferencing
of the "work" pointer in the expression "work->handler"

As were discussed before in PR #35664 it is not true.
Add explanation comment, because static code analysis tool
raised false-positive violation there.

Signed-off-by: Maksim Masalski <maksim.masalski@intel.com>