misc: clippy: add needless_pass_by_value

This is a follow-up of [0].

# Advantages

- This saves dozens of unneeded clone()s across the whole code base
- Makes it much easier to reason about how parameters are used
  (often we passed owned Arc/Rc versions without actually needing
  ownership)

# Exceptions

For certain code paths, the alternatives would require awkward or overly
complex code, and in some cases the functions are the logical owners of
the values they take. In those cases, I've added
#[allow(clippy::needless_pass_by_value)].

This does not mean that one should not improve this in the future.

[0] 6a86c157af

Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
On-behalf-of: SAP philipp.schuster@sap.com

vmm/src/igvm/igvm_loader.rs

@@ -131,7 +131,7 @@ fn import_parameter(
 /// Right now it only supports SNP based isolation.
 /// We can boot legacy VM with an igvm file without
 /// any isolation.
-///
+#[allow(clippy::needless_pass_by_value)]
 pub fn load_igvm(
     mut file: &std::fs::File,
     memory_manager: Arc<Mutex<MemoryManager>>,

vmm/src/igvm/mod.rs

@@ -74,7 +74,7 @@ pub enum BootPageAcceptance {
 /// The startup memory type used to notify a well behaved host that memory should be present before attempting to
 /// start the guest.
 #[allow(dead_code)]
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum StartupMemoryType {
     /// The range is normal memory.
     Ram,