Use `eql` or `eq` instead of `=` in some places

Use `eql` or `eq` instead of `=` in some places

For a switch op to be generated, comparisons must be made using `eq`,
`eql` or `equal`, not `=`.

* lisp/emacs-lisp/byte-opt.el (byte-optimize-lapcode):
* lisp/files.el (file-modes-char-to-who, file-modes-char-to-right):
* lisp/international/titdic-cnv.el (tit-process-header):
* lisp/language/ethio-util.el (ethio-input-special-character)
(ethio-fidel-to-tex-buffer):
* lisp/language/lao.el (consonant):
Use `eq` or `eql` instead of `=`.

In these cases either `eq` or `eql` would do and the choice does not
affect the resulting code.  We compare numbers with `eql` and
characters with `eq` as a matter of style.