docs: fix rendering for code blocks in SPM

Two sample build command code blocks are not correctly
rendered by the documentation generator.

Fix that by adding newlines.

Signed-off-by: Nicola Mazzucato <nicola.mazzucato@arm.com>
Change-Id: I1bb075ea4fc8e3230307548e40daecf2a79bae8d
diff --git a/docs/components/secure-partition-manager.rst b/docs/components/secure-partition-manager.rst
index f0caf89..871e02b 100644
--- a/docs/components/secure-partition-manager.rst
+++ b/docs/components/secure-partition-manager.rst
@@ -203,6 +203,7 @@
 
 Sample TF-A build command line when FEAT_SEL2 architecture extension is
 implemented and the SPMC is located at S-EL2:
+
 .. code:: shell
 
     make \
@@ -220,6 +221,7 @@
 
 Sample TF-A build command line when FEAT_SEL2 architecture extension is
 implemented, the SPMC is located at S-EL2, and enabling secure boot:
+
 .. code:: shell
 
     make \