netifd: strip mask from IP address in DHCP client params

ipaddr option can be in CIDR notation,
but udhcp wants just an IP address

Signed-off-by: Andrey Erokhin <a.erokhin@inango-systems.com>

package/network/config/netifd/files/lib/netifd/proto/dhcp.sh

@@ -67,7 +67,7 @@ proto_dhcp_setup() {
 		-p /var/run/udhcpc-$iface.pid \
 		-s /lib/netifd/dhcp.script \
 		-f -t 0 -i "$iface" \
-		${ipaddr:+-r $ipaddr} \
+		${ipaddr:+-r ${ipaddr/\/*/}} \
 		${hostname:+-x "hostname:$hostname"} \
 		${vendorid:+-V "$vendorid"} \
 		$clientid $defaultreqopts $broadcast $norelease $dhcpopts