dnsmasq: since this was always based on a hardwired /etc/hosts...

The regdhcp conditional option never really worked in the first place.
Dhcplease registration is controlled by regdhcp and regdhcpstatic
elsewhere already and we always need to include this file.

PR: https://forum.opnsense.org/index.php?topic=4041
(cherry picked from commit f31e5560)

src/etc/inc/plugins.inc.d/dnsmasq.inc

@@ -85,11 +85,7 @@ function dnsmasq_configure_do($verbose = false)
         flush();
     }
 
-    $args = "";
-
-    if (isset($config['dnsmasq']['regdhcp'])) {
-        $args .= " -H /var/etc/dnsmasq-hosts ";
-    }
+    $args = ' -H /var/etc/dnsmasq-hosts ';
 
     /* Setup listen port, if non-default */
     if (isset($config['dnsmasq']['port']) && is_port($config['dnsmasq']['port'])) {