broadcom: fix const-qualifier warns

modules/broadcom/brcm.c

@@ -718,7 +718,7 @@ static int iface_get_4addr(const char *ifname, bool *enabled)
 	return nlwifi_get_4addr(ifname, enabled);
 }
 
-static int iface_get_4addr_parent(const char *ifname, const char *parent)
+static int iface_get_4addr_parent(const char *ifname, char *parent)
 {
 	libwifi_dbg("[%s] %s called\n", ifname, __func__);