Fix a bunch of places where \arg was used instead of \param. Using \arg

Fix a bunch of places where \arg was used instead of \param.  Using \arg
to document arguments seems logical, and does work, but is not the best
thing to use.

\arg in doxygen is simply for creating non-nested unordered lists.  \param is
the correct tag to use to document function parameters, and will come out
better in the generated documentation.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@127401 65c4cc65-6c06-0410-ace0-fbb531ad65f3