udhcp: change UDHCP_DEBUG into int, make verbosity selectable with -v

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

networking/udhcp/arpping.c

@@ -128,6 +128,6 @@ int FAST_FUNC arpping(uint32_t test_ip,
 
  ret:
 	close(s);
-	DEBUG("%srp reply received for this address", rv ? "No a" : "A");
+	log1("%srp reply received for this address", rv ? "No a" : "A");
 	return rv;
 }