misc: virtio-devices: streamline error Display::fmt()

The changes were mostly automatically applied using the Python
script mentioned in the first commit of this series.

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

virtio-devices/src/rng.rs

@@ -41,9 +41,9 @@ enum Error {
     DescriptorChainTooShort,
     #[error("Invalid descriptor")]
     InvalidDescriptor,
-    #[error("Failed to write to guest memory: {0}")]
+    #[error("Failed to write to guest memory")]
     GuestMemoryWrite(#[source] vm_memory::guest_memory::Error),
-    #[error("Failed adding used index: {0}")]
+    #[error("Failed adding used index")]
     QueueAddUsed(#[source] virtio_queue::Error),
 }