Derive PartialEq & Eq in capabilities enum

This helps out when we use the Enum inside error types like
`thiserror::Error`.

Signed-off-by: Babis Chalios <bchalios@amazon.es>

Author: Babis Chalios

src/cap.rs

@@ -20,6 +20,7 @@ use kvm_bindings::*;
 // We are allowing docs to be missing here because this enum is a wrapper
 // over auto-generated code.
 #[allow(missing_docs)]
+#[derive(PartialEq, Eq)]
 pub enum Cap {
     Irqchip = KVM_CAP_IRQCHIP,
     Hlt = KVM_CAP_HLT,