[configure]: update mac_filter help string (#2004)

diff --git a/configure.ac b/configure.ac
index 7cf0d3c..92407ef 100644
--- a/configure.ac
+++ b/configure.ac
@@ -746,7 +746,7 @@
 #
 
 AC_ARG_ENABLE(mac_filter,
-              [AS_HELP_STRING([--enable-mac-filter],[Enable MAC filter support @<:@default=yes@:>@.])],
+              [AS_HELP_STRING([--enable-mac-filter],[Enable MAC filter support @<:@default=no@:>@.])],
     [
         case "${enableval}" in