coverity#735399 Logically dead code

we can only enter the bAssumeExprLParenMode controlled block once
because the block sets bAssumeExprLParenMode to false

bAssumeExprLParenMode is only true if the first token read in the
method is LPAREN

so we can only enter this block if the current token is LPAREN and
its the first token processed, so the token can't be BYVAL

Change-Id: I6e668fca4d127d7dbfe447e2d9f2231e05278a7d

basic/source/comp/exprtree.cxx

@@ -1071,10 +1071,6 @@ SbiParameters::SbiParameters( SbiParser* p, bool bStandaloneExpression, bool bPa
                 {
                     bBracket = true;
                     delete pExpr;
-                    if( bByVal )
-                    {
-                        pParser->Error( SbERR_LVALUE_EXPECTED );
-                    }
                     return;
                 }
             }