fix windows build

by reverting part of commit
    commit 7419057e
    Author: Noel Grandin <noel@peralex.com>
    Date:   Thu Sep 22 16:34:14 2016 +0200
    loplugin:unusedmethods in chart2..svx

Change-Id: I72515c9b5f3739f57d4b63a724a9fa32075b2612
Reviewed-on: https://gerrit.libreoffice.org/29197Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Noel Grandin <noel.grandin@collabora.co.uk>

include/basic/sbxvar.hxx

@@ -119,6 +119,8 @@ public:
     const SbxValues& GetValues_Impl() const { return aData; }
     bool Put( const SbxValues& );
 
+    SbxValues * data() { return &aData; }
+
     sal_Unicode GetChar() const;
     sal_Int16   GetInteger() const;
     sal_Int32   GetLong() const;