Fix compiler warning in MessageBufferDemo.c (FreeRTOS#842)

* prvReceiverTask() in MessageBufferDemo.c declared a variable as a "MessageBufferHandle_t *" instead of just a "MessageBuffer_t".  This came to light when updating the kernel submodule pointer as the underlying datatype changed in the kernel from a void *.

* Remove additional line that was preventing automated uncrustify tests from passing.

Co-authored-by: none <>

FreeRTOS/Demo/Common/Minimal/MessageBufferDemo.c

@@ -661,7 +661,7 @@ static void prvNonBlockingReceiverTask( void * pvParameters )
 
     static void prvReceiverTask( void * pvParameters )
     {
-        MessageBufferHandle_t * const pxMessageBuffer = ( MessageBufferHandle_t * ) pvParameters;
+        MessageBufferHandle_t const pxMessageBuffer = ( MessageBufferHandle_t ) pvParameters;
         char cExpectedString[ 12 ]; /* Large enough to hold a 32-bit number in ASCII. */
         char cReceivedString[ 12 ]; /* Large enough to hold a 32-bit number in ASCII. */
         int32_t iExpectedData = 0;