find-provides.ksyms: add a short description of the parsing logic
    
    Add a comment that, hopefully, sheds some light on what is going on in
    the following code.
    
    * find-provides.ksyms: Add a comment.
    
    Co-Authored-by: Denys Vlasenko <dvlasenk@redhat.com>
    Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>