only run pxe late hook if $ip is given

Signed-off-by: Christian Hesse <mail@eworm.de>

archiso/initcpio/hooks/archiso_pxe_common

@@ -47,6 +47,7 @@ run_hook () {
 }
 
 run_latehook () {
+    if [[ -n "${ip}" ]]; then
         [[ -z "${copy_resolvconf}" ]] && copy_resolvconf="y"
 
         if [[ "${copytoram}" == "y" ]]; then
@@ -55,4 +56,5 @@ run_latehook () {
         elif [[ "${copy_resolvconf}" != "n" && -f /etc/resolv.conf ]]; then
             cp /etc/resolv.conf /new_root/etc/resolv.conf
         fi
+    fi
 }