USHRT_MAX -> SAL_MAX_UINT16

...as nH needs to fit into the following SwPosSize::Height call's parameter of
type sal_uInt16.  And whatever the reason to check for < instead of
<= USHRT_MAX...

Change-Id: I0377d51e7411eef7913d951eb972214a8d8d5768
Reviewed-on: https://gerrit.libreoffice.org/49065Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

sw/source/core/text/itrform2.cxx

@@ -2388,7 +2388,7 @@ void SwTextFormatter::CalcFlyWidth( SwTextFormatInfo &rInf )
         if( nNextTop > aInter.Bottom() )
         {
             SwTwips nH = nNextTop - aInter.Top();
-            if( nH < USHRT_MAX )
+            if( nH < SAL_MAX_UINT16 )
                 pFly->Height( sal_uInt16( nH ) );
         }
         if( nAscent < pFly->Height() )