pvmfw: Perform DICE derivation

Integrate DICE derivation into pvmfw and fail if the operation fails.

Note that we still need to get the salt ("hidden" DICE input) from the
instance.img or TRNG and pass the result to the next stage.

Bug: 256827715
Test: atest MicrodroidHostTests
Change-Id: Ibebaf526fd6055b9d05ce6017b560fb8814471e5
diff --git a/pvmfw/src/entry.rs b/pvmfw/src/entry.rs
index 1b35c79..52e7a22 100644
--- a/pvmfw/src/entry.rs
+++ b/pvmfw/src/entry.rs
@@ -48,6 +48,8 @@
     InvalidRamdisk,
     /// Failed to verify the payload.
     PayloadVerificationError,
+    /// DICE layering process failed.
+    SecretDerivationError,
 }
 
 main!(start);