dropbear: Add --disable-utmpx again

The option --disable-utmpx was deleted by accident in commit 7545c1d;
add it again to the CONFIGURE_ARGS list

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>

package/network/services/dropbear/Makefile

@@ -68,6 +68,7 @@ CONFIGURE_ARGS += \
 	--enable-syslog \
 	$(if $(CONFIG_SHADOW_PASSWORDS),,--disable-shadow) \
 	--disable-lastlog \
+	--disable-utmpx \
 	$(if $(CONFIG_DROPBEAR_UTMP),,--disable-utmp) \
 	--disable-wtmp \
 	--disable-wtmpx \