nStart/EndEEIndex nned not be bounded by sal_uInt16

...it appears, since ESelection's nStart/EndPos have been changed to sal_Int32
with 3cbfcee3 "xub_StrLen and tools/string.hxx
final straw".

Change-Id: I3f3d77d6efeabef9f05b3a5233e0e5590b1ed365
Reviewed-on: https://gerrit.libreoffice.org/48767Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

editeng/source/accessibility/AccessibleEditableTextPara.cxx

@@ -339,8 +339,8 @@ namespace accessibility
     ESelection AccessibleEditableTextPara::MakeSelection( sal_Int32 nStartEEIndex, sal_Int32 nEndEEIndex )
     {
         // check overflow
-        DBG_ASSERT(nStartEEIndex >= 0 && nStartEEIndex <= USHRT_MAX &&
-                   nEndEEIndex >= 0 && nEndEEIndex <= USHRT_MAX &&
+        DBG_ASSERT(nStartEEIndex >= 0 &&
+                   nEndEEIndex >= 0 &&
                    GetParagraphIndex() >= 0 && GetParagraphIndex() <= SAL_MAX_INT32,
                    "AccessibleEditableTextPara::MakeSelection: index value overflow");