Fix Manifest definition in GettingStarted.md

Fixes required for the sample manifest to work.

Change-Id: Ie5ca7eddde9b616895147277e4b4e41f3036b249
diff --git a/docs/GettingStarted.md b/docs/GettingStarted.md
index 8f4d920..de60e50 100644
--- a/docs/GettingStarted.md
+++ b/docs/GettingStarted.md
@@ -59,9 +59,11 @@
 
 &{/} {
 	hypervisor {
+		compatible = "hafnium,hafnium";
 		vm1 {
 			debug_name = "Linux VM";
 			kernel_filename = "vmlinuz";
+			ramdisk_filename = "initrd.img";
 		};
 	};
 };