Agere Posts Loss on Revenue Drop, Charges  NEW YORK (Reuters) - Agere Systems Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=AGRa.N target=/stocks/quickinfo/fullquote"&gt;AGRa.N&lt;/A&gt; on Tuesday  posted a fiscal fourth-quarter loss as the communications chip  maker's revenue declined and it took hefty charges for  restructuring.