add protection against running cf2nand from yaffs2

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@5301 3c298f89-4303-0410-b956-a3cf2f4a3e73

package/base-files/rb532-2.6/sbin/cf2nand

@@ -16,6 +16,11 @@ copy_kernel() {
 }
 
 fstype="$(mount | grep ' / ' | awk '{print $5}')"
+case "$fstype" in
+	ext2|jffs2) echo "Copying from $fstype to yaffs2";;
+	*) echo "Invalid filesystem."; exit 1;;
+esac
+
 [ -d /tmp/cf2nand ] && {
 	echo "/tmp/cf2nand already exists"
 	exit 1