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/docs/platform-interrupt-controller-API.rst b/docs/platform-interrupt-controller-API.rst
index 230a990..ad68709 100644
--- a/docs/platform-interrupt-controller-API.rst
+++ b/docs/platform-interrupt-controller-API.rst
@@ -22,7 +22,7 @@
 
 This API should return the priority of the interrupt the PE is currently
 servicing. This must be be called only after an interrupt has already been
-acknowledged via. ``plat_ic_acknowledge_interrupt``.
+acknowledged via ``plat_ic_acknowledge_interrupt``.
 
 In the case of Arm standard platforms using GIC, the *Running Priority Register*
 is read to determine the priority of the interrupt.