vmm: simplify EntryPoint

EntryPoint had an optional entry_addr, but there is no usage of this
struct that makes it necessary that the address is optional.

Remove the Option to avoid being able to express things that are not
useful.

Signed-off-by: Julian Stecklina <julian.stecklina@cyberus-technology.de>

vmm/src/vm.rs

@@ -980,9 +980,7 @@ impl Vm {
         if let PvhEntryPresent(entry_addr) = entry_addr.pvh_boot_cap {
             // Use the PVH kernel entry point to boot the guest
             info!("Kernel loaded: entry_addr = 0x{:x}", entry_addr.0);
-            Ok(EntryPoint {
-                entry_addr: Some(entry_addr),
-            })
+            Ok(EntryPoint { entry_addr })
         } else {
             Err(Error::KernelMissingPvhHeader)
         }