add nfsroot example, nfsver=3 is important

package/dnsmasq/files/dnsmasq.conf

@@ -35,3 +35,7 @@ dhcp-option=6,0.0.0.0
 dhcp-option=42,0.0.0.0
 # WINS server(s):
 #dhcp-option=44,0.0.0.0
+
+# nfsroot example for a host
+#dhcp-host=00:0c:42:0a:7d:d3,10.0.0.4,net:rb532
+#dhcp-option=rb532,option:root-path,/nfsroot/rb532,nfsvers=3