[dice] Remove redundant feature flag alloc

The feature flag alloc is not needed as it has been used in both
std and non-std open-dice libraries.

Test: atest MicrodroidHostTests
Bug: 357008987
Change-Id: I0999284c23a6ca2567e20698761dee60113b534d
diff --git a/libs/dice/open_dice/Android.bp b/libs/dice/open_dice/Android.bp
index b3cb651..b4181e2 100644
--- a/libs/dice/open_dice/Android.bp
+++ b/libs/dice/open_dice/Android.bp
@@ -19,9 +19,6 @@
         "libopen_dice_cbor_bindgen_nostd",
         "libzeroize_nostd",
     ],
-    features: [
-        "alloc",
-    ],
     whole_static_libs: [
         "libcrypto_baremetal",
     ],
@@ -43,7 +40,6 @@
         "libzeroize",
     ],
     features: [
-        "alloc",
         "serde_derive",
         "std",
     ],
diff --git a/libs/dice/open_dice/src/lib.rs b/libs/dice/open_dice/src/lib.rs
index 16c2b96..66e93cf 100644
--- a/libs/dice/open_dice/src/lib.rs
+++ b/libs/dice/open_dice/src/lib.rs
@@ -17,7 +17,6 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
-#[cfg(feature = "alloc")]
 extern crate alloc;
 
 #[cfg(not(feature = "std"))]
@@ -27,7 +26,6 @@
 mod dice;
 mod error;
 mod ops;
-#[cfg(feature = "alloc")]
 mod retry;
 
 pub use bcc::{
@@ -44,7 +42,6 @@
 pub use ops::{
     derive_cdi_leaf_priv, generate_certificate, hash, kdf, keypair_from_seed, sign, verify,
 };
-#[cfg(feature = "alloc")]
 pub use retry::{
     retry_bcc_format_config_descriptor, retry_bcc_main_flow, retry_dice_main_flow,
     retry_generate_certificate, OwnedDiceArtifacts,
diff --git a/libs/dice/open_dice/src/retry.rs b/libs/dice/open_dice/src/retry.rs
index d9551f3..6e75e91 100644
--- a/libs/dice/open_dice/src/retry.rs
+++ b/libs/dice/open_dice/src/retry.rs
@@ -23,7 +23,6 @@
 };
 use crate::error::{DiceError, Result};
 use crate::ops::generate_certificate;
-#[cfg(feature = "alloc")]
 use alloc::vec::Vec;
 #[cfg(feature = "serde_derive")]
 use serde_derive::{Deserialize, Serialize};