Remove compiler warnings.

Demo/CORTEX_LPC1768_GCC_Rowley/LPCUSB/USB_CDC.c

@@ -46,6 +46,7 @@
 */
 
 #include "FreeRTOS.h"
+#include "task.h"
 #include "queue.h"
 
 #include <stdio.h>

Demo/CORTEX_LPC1768_GCC_Rowley/LPCUSB/usbcontrol.c

@@ -109,6 +109,7 @@ static void StallControlPipe(unsigned char bEPStat)
 	unsigned char	*pb;
 	int	i;
 
+	( void ) bEPStat;
 	USBHwEPStall(0x80, TRUE);
 
 // dump setup packet

Demo/CORTEX_LPC1768_GCC_Rowley/LPCUSB/usbstdreq.c

@@ -104,6 +104,7 @@ BOOL USBGetDescriptor(unsigned short wTypeIndex, unsigned short wLangID, int *pi
 	unsigned char	*pab;
 	int iCurIndex;
 
+	( void ) wLangID;
 	ASSERT(pabDescrip != NULL);
 
 	bType = GET_DESC_TYPE(wTypeIndex);