Fix clippy errors and some warnings.

TEST=cargo test

Change-Id: I91afe78141c717a592eec5ec77acac2a500ba163
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2623941
Tested-by: kokoro <noreply+kokoro@google.com>
Tested-by: Keiichi Watanabe <keiichiw@chromium.org>
Reviewed-by: Andrew Walbran <qwandor@google.com>
Reviewed-by: Keiichi Watanabe <keiichiw@chromium.org>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
Commit-Queue: Andrew Walbran <qwandor@google.com>
diff --git a/src/main.rs b/src/main.rs
index 5d02af0..d8645e5 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -598,8 +598,8 @@
 
     if let Some(s) = s {
         let opts = s
-            .split(",")
-            .map(|frag| frag.split("="))
+            .split(',')
+            .map(|frag| frag.split('='))
             .map(|mut kv| (kv.next().unwrap_or(""), kv.next().unwrap_or("")));
 
         for (k, v) in opts {
@@ -759,7 +759,7 @@
                     SerialHardware::Serial => {}
                     _ => {
                         return Err(argument::Error::InvalidValue {
-                            value: serial_params.hardware.to_string().to_owned(),
+                            value: serial_params.hardware.to_string(),
                             expected: String::from("earlycon not supported for hardware"),
                         });
                     }
@@ -1187,7 +1187,7 @@
                         })?;
 
                         let dur = Duration::from_secs(seconds);
-                        shared_dir.fs_cfg.entry_timeout = dur.clone();
+                        shared_dir.fs_cfg.entry_timeout = dur;
                         shared_dir.fs_cfg.attr_timeout = dur;
                     }
                     "cache" => {