fix(fdt): Improve reporting of errors related to FDT setup

Change the doc comment (which also affects the implementation of
`std::fmt::Display`) for `ConfigurationError::SetupFDT` to include
the underlying `fdt::FtdError`.
This improves both the reporting of failures during FDT setup on the
logs, as well as the message in API server's corresponding HTTP
response.

Signed-off-by: Christos Katsakioris <ckatsak@cslab.ece.ntua.gr>
Signed-off-by: Filippos Tofalos <phtof@cslab.ece.ntua.gr>

Author: ckatsak

src/vmm/src/arch/aarch64/mod.rs

@@ -28,7 +28,7 @@ use crate::vstate::memory::{Address, Bytes, GuestAddress, GuestMemory, GuestMemo
 /// Errors thrown while configuring aarch64 system.
 #[derive(Debug, thiserror::Error, displaydoc::Display)]
 pub enum ConfigurationError {
-    /// Failed to create a Flattened Device Tree for this aarch64 microVM.
+    /// Failed to create a Flattened Device Tree for this aarch64 microVM: {0}
     SetupFDT(#[from] fdt::FdtError),
     /// Failed to compute the initrd address.
     InitrdAddress,