avmd:Make libavmd no_std

Bug: 240459942
Test: m avmdtool
Change-Id: I395ddd7aba970c5ff94b8eff7b8d06a553ff036d
diff --git a/avmd/src/lib.rs b/avmd/src/lib.rs
index 9722518..7a06e6a 100644
--- a/avmd/src/lib.rs
+++ b/avmd/src/lib.rs
@@ -14,6 +14,8 @@
 
 //! Library for handling AVMD blobs.
 
+#![no_std]
+
 mod avmd;
 
 pub use avmd::{ApkDescriptor, Avmd, Descriptor, ResourceIdentifier, VbMetaDescriptor};