pftop size sort is same as none
diag_pftop.php has "Size" for sorttype which is not a order type
known by pftop. (sort_size_callback in pftop is "Bytes".)
Size is not a sort option and is same as "none".
(I noticed this while working on my book.
My list of bugs is at http://reedmedia.net/books/pfsense/bugs.html )
Remove "size" option from pftop as it does nothing. The "bytes" option is the correct one to use. Fixes #7579