dracut-module-setup.sh: use "*" to expend array as string

As suggested by:
https://github.com/koalaman/shellcheck/wiki/SC2199
The array is not quoted here but implicitly concatenate still happens,
could be harmless but shellcheck complains about it so fix it.

Signed-off-by: Kairui Song <kasong@redhat.com>
Acked-by: Philipp Rudo <prudo@redhat.com>

dracut-module-setup.sh

@@ -94,7 +94,7 @@ kdump_setup_dns() {
 
     _tmp=$(get_nmcli_value_by_field "$_nm_show_cmd" "IP4.DNS")
     array=(${_tmp//|/ })
-    if [[ ${array[@]} ]]; then
+    if [[ ${array[*]} ]]; then
         for _dns in "${array[@]}"
         do
             echo "nameserver=$_dns" >> "$_dnsfile"