Fix errors from rustc 1.71.0

Bug: 288268986
Test: m rust
Change-Id: If972c3856297978663642c60d162fcc504eb659d
diff --git a/keystore2/src/entropy.rs b/keystore2/src/entropy.rs
index de38187..1dcdc86 100644
--- a/keystore2/src/entropy.rs
+++ b/keystore2/src/entropy.rs
@@ -29,7 +29,7 @@
 /// Register the entropy feeder as an idle callback.
 pub fn register_feeder() {
     crate::globals::ASYNC_TASK.add_idle(|shelf| {
-        let mut info = shelf.get_mut::<FeederInfo>();
+        let info = shelf.get_mut::<FeederInfo>();
         let now = Instant::now();
         let feed_needed = match info.last_feed {
             None => true,