WaE: struct/class inconsistency

Drop a couple of unnecessary forward declarations for classes defined in files
included earlier from the same file.

Change-Id: I9a0a24f88990447d7eafe0438f3713e58f649cf9

sw/source/filter/ww8/ww8par.hxx

@@ -72,9 +72,7 @@ class WW8PLCFMan;
 struct WW8PLCFManResult;
 class WW8RStyle;
 class WW8PLCF_HdFt;
-class WW8Dop;
 class WW8ScannerBase;
-struct WW8FieldDesc;
 struct WW8FlyPara;
 struct WW8SwFlyPara;
 struct WW8_PIC;