fix(docs): fixes to the docs to fix build errors

An empty line is required between delaring a code block and its
contents. This wasn't the case for a couple of blocks in prerequisites,
the patch adds them.

Fixed reference in secure-partition-manager.rst

Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
Change-Id: Ib89819b66de4ec2c33b5dc4bceadeff4faf79cfc
diff --git a/docs/getting_started/prerequisites.rst b/docs/getting_started/prerequisites.rst
index 40d574f..1e3178d 100644
--- a/docs/getting_started/prerequisites.rst
+++ b/docs/getting_started/prerequisites.rst
@@ -64,11 +64,13 @@
 'checkpatch.pl' script from linux source tree. To setup and download 'checkpatch.pl':
 
 .. code:: shell
+
    ./build/setup_checkpatch.sh
 
 Then test it works with:
 
 .. code:: shell
+
    make checkpatch
 
 Documentation