tree-wide: drop some unneeded allow clauses

Signed-off-by: Wei Liu <liuwe@microsoft.com>

arch/src/x86_64/mod.rs

@@ -202,7 +202,7 @@ impl From<Error> for super::Error {
     }
 }
 
-#[allow(dead_code, clippy::upper_case_acronyms)]
+#[allow(clippy::upper_case_acronyms)]
 #[derive(Copy, Clone, Debug)]
 pub enum CpuidReg {
     EAX,

arch/src/x86_64/smbios.rs

@@ -15,7 +15,6 @@ use std::slice;
 use vm_memory::ByteValued;
 use vm_memory::{Address, Bytes, GuestAddress};
 
-#[allow(unused_variables)]
 #[derive(Debug)]
 pub enum Error {
     /// There was too little guest memory to store the entire SMBIOS table.