x230: increase rpi's spispeed

While I think I have initially used 128 from some libreboot docs and never
had problems with it, I don't really see anybody use less than 512 right
now.

x230/external_install_bottom.sh

@@ -115,7 +115,7 @@ if [ ! "$have_flasher" -gt 0 ] ; then
 fi
 
 if [ ! "${rpi_frequency}" -gt 0 ] ; then
-	rpi_frequency=128
+	rpi_frequency=512
 fi
 
 programmer=""

x230/external_install_top.sh

@@ -132,7 +132,7 @@ if [ ! "$have_flasher" -gt 0 ] ; then
 fi
 
 if [ ! "${rpi_frequency}" -gt 0 ] ; then
-	rpi_frequency=128
+	rpi_frequency=512
 fi
 
 programmer=""