staging: speakup: Fix multi-line comment style

Thus using the preferred style for multi-line coments as
mentioned in Documentation/CodingStyle.

It also silences 'Block comments use * on subsequent lines'
and 'Block comments use a trailing */ on a separate line'
checkpatch.pl warnings.

Signed-off-by: Cristina Moraru <cristina.moraru09@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>