misc: Fix missing lifetime syntax clippy warning

This was caught by the nightly compiler during cargo fuzz build.

error: lifetime flowing from input to output with different syntax can be confusing
   --> /home/runner/work/cloud-hypervisor/cloud-hypervisor/hypervisor/src/arch/x86/emulator/mod.rs:493:26
    |
493 |     pub fn new(platform: &mut dyn PlatformEmulator<CpuState = T>) -> Emulator<T> {
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^     ----------- the lifetime gets resolved as `'_`
    |                          |
    |                          this lifetime flows to the output
    |
    = note: `-D mismatched-lifetime-syntaxes` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(mismatched_lifetime_syntaxes)]`
help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
    |
493 |     pub fn new(platform: &mut dyn PlatformEmulator<CpuState = T>) -> Emulator<'_, T> {

Signed-off-by: Jinank Jain <jinankjain@microsoft.com>

block/src/fixed_vhd_async.rs

@@ -34,7 +34,7 @@ impl DiskFile for FixedVhdDiskAsync {
         ) as Box<dyn AsyncIo>)
     }
 
-    fn fd(&mut self) -> BorrowedDiskFd {
+    fn fd(&mut self) -> BorrowedDiskFd<'_> {
         BorrowedDiskFd::new(self.0.as_raw_fd())
     }
 }

block/src/fixed_vhd_sync.rs

@@ -34,7 +34,7 @@ impl DiskFile for FixedVhdDiskSync {
         ) as Box<dyn AsyncIo>)
     }
 
-    fn fd(&mut self) -> BorrowedDiskFd {
+    fn fd(&mut self) -> BorrowedDiskFd<'_> {
         BorrowedDiskFd::new(self.0.as_raw_fd())
     }
 }

block/src/qcow/vec_cache.rs

@@ -111,7 +111,7 @@ impl<T: Cacheable> CacheMap<T> {
         self.map.get_mut(&index)
     }
 
-    pub fn iter_mut(&mut self) -> IterMut<usize, T> {
+    pub fn iter_mut(&mut self) -> IterMut<'_, usize, T> {
         self.map.iter_mut()
     }
 

block/src/qcow_sync.rs

@@ -39,7 +39,7 @@ impl DiskFile for QcowDiskSync {
         Ok(Box::new(QcowSync::new(self.qcow_file.clone())) as Box<dyn AsyncIo>)
     }
 
-    fn fd(&mut self) -> BorrowedDiskFd {
+    fn fd(&mut self) -> BorrowedDiskFd<'_> {
         let lock = self.qcow_file.lock().unwrap();
         BorrowedDiskFd::new(lock.as_raw_fd())
     }
@@ -63,7 +63,7 @@ impl QcowSync {
 }
 
 impl AsyncAdaptor<QcowFile> for Arc<Mutex<QcowFile>> {
-    fn file(&mut self) -> MutexGuard<QcowFile> {
+    fn file(&mut self) -> MutexGuard<'_, QcowFile> {
         self.lock().unwrap()
     }
 }

block/src/raw_async.rs

@@ -47,7 +47,7 @@ impl DiskFile for RawFileDisk {
         }
     }
 
-    fn fd(&mut self) -> BorrowedDiskFd {
+    fn fd(&mut self) -> BorrowedDiskFd<'_> {
         BorrowedDiskFd::new(self.file.as_raw_fd())
     }
 }

block/src/raw_async_aio.rs

@@ -50,7 +50,7 @@ impl DiskFile for RawFileDiskAio {
         }
     }
 
-    fn fd(&mut self) -> BorrowedDiskFd {
+    fn fd(&mut self) -> BorrowedDiskFd<'_> {
         BorrowedDiskFd::new(self.file.as_raw_fd())
     }
 }

block/src/raw_sync.rs

@@ -44,7 +44,7 @@ impl DiskFile for RawFileDiskSync {
         }
     }
 
-    fn fd(&mut self) -> BorrowedDiskFd {
+    fn fd(&mut self) -> BorrowedDiskFd<'_> {
         BorrowedDiskFd::new(self.file.as_raw_fd())
     }
 }

block/src/vhdx_sync.rs

@@ -39,7 +39,7 @@ impl DiskFile for VhdxDiskSync {
         )
     }
 
-    fn fd(&mut self) -> BorrowedDiskFd {
+    fn fd(&mut self) -> BorrowedDiskFd<'_> {
         let lock = self.vhdx_file.lock().unwrap();
         BorrowedDiskFd::new(lock.as_raw_fd())
     }
@@ -62,7 +62,7 @@ impl VhdxSync {
 }
 
 impl AsyncAdaptor<Vhdx> for Arc<Mutex<Vhdx>> {
-    fn file(&mut self) -> MutexGuard<Vhdx> {
+    fn file(&mut self) -> MutexGuard<'_, Vhdx> {
         self.lock().unwrap()
     }
 }