Minor changes to documentation and comments

Fix some typos and clarify some sentences.

Change-Id: Id276d1ced9a991b4eddc5c47ad9a825e6b29ef74
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/include/lib/el3_runtime/pubsub.h b/include/lib/el3_runtime/pubsub.h
index eb91286..9c303f5 100644
--- a/include/lib/el3_runtime/pubsub.h
+++ b/include/lib/el3_runtime/pubsub.h
@@ -49,7 +49,7 @@
 /*
  * Have the function func called back when the specified event happens. This
  * macro places the function address into the pubsub section, which is picked up
- * and invoked by the invoke_pubsubs() function via. the PUBLISH_EVENT* macros.
+ * and invoked by the invoke_pubsubs() function via the PUBLISH_EVENT* macros.
  *
  * The extern declaration is there to satisfy MISRA C-2012 rule 8.4.
  */