vmbase: Add basic logger

Introduce a logger in vmbase that wraps around the println! into UART to
be able to distinguish different levels of log messages.

Test: atest vmbase_example.integration_test
Change-Id: Id3b98ef4cdc4b23a11f099d75cc1c9902a9da785
diff --git a/vmbase/Android.bp b/vmbase/Android.bp
index e88420e..4c5e9d1 100644
--- a/vmbase/Android.bp
+++ b/vmbase/Android.bp
@@ -9,6 +9,7 @@
     srcs: ["src/lib.rs"],
     edition: "2021",
     rustlibs: [
+        "liblog_rust_nostd",
         "libpsci",
         "libspin_nostd",
     ],