Document the MIPS -mvxworks-pic option

[Thiemo Seufer]

Richard Sandiford wrote:
> When I submitted the MIPS VxWorks support, I forgot to document
> -mvxworks-pic.  Tsk.  As penance, I've added some documentation for
> -KPIC too; it was listed in the overview, but not in the main table.
> 
> Other options are missing documentation too, but I don't have time
> for a full overhaul.  I hope this patch is at least a strict
> improvement on what we have now.
> 
> Tested on mips-wrs-vxworks.  OK to install?
> 
> Richard
> 
> 
> 	* doc/as.texinfo: Add -mvxworks-pic to the list of MIPS options.
> 	* doc/c-mips.texi (-KPIC, -mvxworks-pic): Document.
> 	* config/tc-mips.c (md_show_usage): Mention -mvxworks-pic.

Ok.


Thiemo