Reword LOAD_IMAGE_V2 in user guide & fix a typo

Change-Id: Id2639218dfffec84d8b0fa295d7e896129d4fcd7
Signed-off-by: John Tsichritzis <john.tsichritzis@arm.com>
diff --git a/docs/porting-guide.rst b/docs/porting-guide.rst
index 5462cc1..603d44a 100644
--- a/docs/porting-guide.rst
+++ b/docs/porting-guide.rst
@@ -952,9 +952,9 @@
     Argument : void
     Return   : void
 
-This api allows a platform to disable the Accelerator Coherency Port (if
+This API allows a platform to disable the Accelerator Coherency Port (if
 present) during a cluster power down sequence. The default weak implementation
-doesn't do anything. Since this api is called during the power down sequence,
+doesn't do anything. Since this API is called during the power down sequence,
 it has restrictions for stack usage and it can use the registers x0 - x17 as
 scratch registers. It should preserve the value in x18 register as it is used
 by the caller to store the return address.