fix(external-hdf):Force link to XSA

* Usefull if rebuilding

recipes-bsp/hdf/external-hdf.bbappend

@@ -24,7 +24,7 @@ do_install_prepend() {
     # Link .xsa file to match Techlab install
     for VARIANT in ${PL_VARIANTS}; do
         mkdir -p ${WORKDIR}/${VARIANT}
-        ln -s ${S}/${VARIANT}_${HDF_PATH} ${VARIANT}/${HDF_PATH}
+        ln -sf ${S}/${VARIANT}_${HDF_PATH} ${VARIANT}/${HDF_PATH}
     done
 
 }