doc: Set correct syntax highlighting style

Several code blocks do not specify a language for syntax
highlighting. This results in Sphinx using a default highlighter
which is Python.

This patch adds the correct language to each code block that doesn't
already specify it.

Change-Id: Icce1949aabfdc11a334a42d49edf55fa673cddc3
Signed-off-by: Paul Beesley <paul.beesley@arm.com>
diff --git a/docs/design/psci-pd-tree.rst b/docs/design/psci-pd-tree.rst
index e52da77..56a6d6f 100644
--- a/docs/design/psci-pd-tree.rst
+++ b/docs/design/psci-pd-tree.rst
@@ -109,7 +109,7 @@
 
 This tree is defined by the platform as the array described above as follows:
 
-::
+.. code:: c
 
         #define PLAT_NUM_POWER_DOMAINS       20
         #define PLATFORM_CORE_COUNT          13
@@ -219,7 +219,7 @@
 The power domain tree is implemented as a combination of the following data
 structures.
 
-::
+.. code:: c
 
     non_cpu_pd_node_t psci_non_cpu_pd_nodes[PSCI_NUM_NON_CPU_PWR_DOMAINS];
     cpu_pd_node_t psci_cpu_pd_nodes[PLATFORM_CORE_COUNT];