Add some more prerequisites.

Change-Id: Ifc8cb90b546a1b375009f2965e5281b63fa56e9b
diff --git a/docs/GettingStarted.md b/docs/GettingStarted.md
index 8813bf7..3d58d26 100644
--- a/docs/GettingStarted.md
+++ b/docs/GettingStarted.md
@@ -22,7 +22,7 @@
 Install prerequisites:
 
 ``` shell
-sudo apt install make binutils-aarch64-linux-gnu
+sudo apt install make binutils-aarch64-linux-gnu device-tree-compiler libssl-dev
 ```
 
 By default, the hypervisor is built with clang for a few target platforms along