Lint: Fix cargo clippy errors for s390x

Some linting errors were identified during the enablement of `make check`.
These have not been found by the Jenkins CI job because `make test` was
only triggered.

The errors for the `agent` occurs under the s390x specific tests while
the other ones for the `kata-ctl` are the architecture-specific code.

This commit is to fix those errors.

Signed-off-by: Hyounggyu Choi <Hyounggyu.Choi@ibm.com>

src/agent/src/device.rs

@@ -1563,7 +1563,7 @@ mod tests {
 
         // Valid path
         let device = ccw::Device::from_str(relpath).unwrap();
-        let matcher = VirtioBlkCCWMatcher::new(&root_bus, &device);
+        let matcher = VirtioBlkCCWMatcher::new(root_bus, &device);
         assert!(matcher.is_match(&uev));
 
         // Invalid paths
@@ -1794,12 +1794,7 @@ mod tests {
         assert!(!matcher.is_match(&uev_remove));
 
         let mut uev_other_device = uev.clone();
-        uev_other_device.devpath = format!(
-            "{}/card{}/{}",
-            AP_ROOT_BUS_PATH,
-            card,
-            format!("{}.0002", card)
-        );
+        uev_other_device.devpath = format!("{}/card{}/{}.0002", AP_ROOT_BUS_PATH, card, card);
         assert!(!matcher.is_match(&uev_other_device));
     }
 }

src/tools/kata-ctl/src/arch/s390x/mod.rs

@@ -104,11 +104,11 @@ mod arch_specific {
 
         let check_fn = if search_values.is_empty() {
             |param: &str, search_param: &str, _search_values: &[&str]| {
-                return param.eq_ignore_ascii_case(search_param);
+                param.eq_ignore_ascii_case(search_param)
             }
         } else {
             |param: &str, search_param: &str, search_values: &[&str]| {
-                let split: Vec<&str> = param.splitn(2, "=").collect();
+                let split: Vec<&str> = param.splitn(2, '=').collect();
                 if split.len() < 2 || split[0] != search_param {
                     return false;
                 }