FDA Warns Cyberonics on Manufacturing  CHICAGO (Reuters) - U.S. regulators warned Cyberonics Inc.  &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=CYBX.O target=/stocks/quickinfo/fullquote"&gt;CYBX.O&lt;/A&gt; of manufacturing deficiencies at the Houston plant  that makes its sole product, an implantable device to treat  epilepsy, the company said on Monday.