tool: fix case when no domains are specified

Signed-off-by: Ivan-Velickovic <i.velickovic@unsw.edu.au>

Author: Ivan-Velickovic

tool/microkit/src/main.rs

@@ -3419,6 +3419,17 @@ fn main() -> Result<(), String> {
             out.extend(timeslice.length.to_le_bytes());
         }
 
+        kernel_elf.write_symbol("ksDomSchedule", &out)?;
+    } else {
+        kernel_elf.write_symbol(
+            "ksDomScheduleLength",
+            &(1_u64.to_le_bytes()),
+        )?;
+
+        let mut out = Vec::with_capacity(16);
+        out.extend(0_u64.to_le_bytes());
+        out.extend(1_u64.to_le_bytes());
+
         kernel_elf.write_symbol("ksDomSchedule", &out)?;
     }