blinky - Use console/stub instead of console/full.

Blinky doesn't use the console at all, so we can minimize the app
further by using the stub console package.

apps/blinky/pkg.yml

diff --git a/apps/blinky/pkg.yml b/apps/blinky/pkg.yml
index d870082..341a7ba 100644
--- a/apps/blinky/pkg.yml
+++ b/apps/blinky/pkg.yml
@@ -27,4 +27,4 @@
 pkg.deps:
     - "@apache-mynewt-core/kernel/os"
     - "@apache-mynewt-core/hw/hal"
-    - "@apache-mynewt-core/sys/console/full"
+    - "@apache-mynewt-core/sys/console/stub"