Fix serial boot functionality for Mynewt

Signed-off-by: Fabio Utzig <utzig@apache.org>
diff --git a/boot/mynewt/syscfg.yml b/boot/mynewt/syscfg.yml
index 0ab9a14..778ba5f 100644
--- a/boot/mynewt/syscfg.yml
+++ b/boot/mynewt/syscfg.yml
@@ -30,3 +30,4 @@
     SYSINIT_CONSTRAIN_INIT: 0
     OS_SCHEDULING: 0
     OS_CPUTIME_TIMER_NUM: -1
+    CONSOLE_COMPAT: 1