Add toybox to the base qemu image.

Change-Id: Ia2a86de23668fb9e59e71f5256f06c9a7225caaa
diff --git a/qemu_base.mk b/qemu_base.mk
index f6929aa..33c1eda 100644
--- a/qemu_base.mk
+++ b/qemu_base.mk
@@ -65,6 +65,7 @@
     servicemanager \
     sh \
     toolbox \
+    toybox \
     vold \
 
 # SELinux packages