disable deferred rendering on ATI Macs until SH-1618 is solved

indra/newview/featuretable_mac.txt

-version 23
+version 24
 
 // NOTE: This is mostly identical to featuretable_mac.txt with a few differences
 // Should be combined into one table
@@ -282,6 +282,7 @@ list TexUnit8orLess
 RenderDeferredSSAO			0	0
 
 list ATI
+RenderDeferred				0	0
 RenderDeferredSSAO			0	0
 
 list Intel