Hi all,

I have just committed this simple and obvious patch to fix a typo for 
"^" multiple alternative constraints in md.texi.
Doc builds Okay.

SVN revision link:
https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=221152

ChangeLog:

2015-03-03  Renlin Li  <renlin.li@arm.com>

     * gcc/doc/md.texi (@item ^): Change ? into ^.