Fix lints introduced in 1.68.2

- `Default` implementations for enums can now be derived in more cases.

Signed-off-by: Patrick Roy <roypat@amazon.co.uk>

Author: roypat

src/loader/x86_64/elf/mod.rs

@@ -104,7 +104,7 @@ impl fmt::Display for Error {
 
 impl std::error::Error for Error {}
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Clone, Default, Copy, Debug, PartialEq, Eq)]
 /// Availability of PVH entry point in the kernel, which allows the VMM
 /// to use the PVH boot protocol to start guests.
 pub enum PvhBootCapability {
@@ -113,15 +113,10 @@ pub enum PvhBootCapability {
     /// PVH entry point is not present
     PvhEntryNotPresent,
     /// PVH entry point is ignored, even if available
+    #[default]
     PvhEntryIgnored,
 }
 
-impl Default for PvhBootCapability {
-    fn default() -> Self {
-        PvhBootCapability::PvhEntryIgnored
-    }
-}
-
 impl fmt::Display for PvhBootCapability {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         use self::PvhBootCapability::*;