Fix a build break with ARM compiler

Author: linlingao

targets/TARGET_TI/TARGET_CC32XX/TARGET_CC3220SF/device/system_CC3220SF.c

@@ -62,3 +62,12 @@ void SystemInit (void)
     SCB->VTOR = (uint32_t) &__Vectors;
     CC3220SF_LAUNCHXL_initGeneral();
 }
+
+/*
+ *  ======== ClockP_getCpuFreq ========
+ */
+void ClockP_getCpuFreq(ClockP_FreqHz *freq)
+{
+    freq->lo = (uint32_t)SystemCoreClock;
+    freq->hi = 0;
+}

targets/TARGET_TI/TARGET_CC32XX/TARGET_CC3220SF/device/system_CC3220SF.h

@@ -32,6 +32,7 @@ extern "C" {
 
 #include <stdio.h>
 #include "ti/drivers/net/wifi/wlan.h"
+#include "ti/drivers/dpl/ClockP.h"
 
 extern uint32_t SystemCoreClock;     /*!< System Clock Frequency (Core Clock)  */
 

targets/TARGET_TI/TARGET_CC32XX/TARGET_CC3220SF/ti/drivers/pwm/PWMTimerCC32XX.c

@@ -152,8 +152,6 @@ static const uint32_t gpioPinIndexes[8] = {
 #define PinConfigPinMode(config)       (((config) >> 8) & 0xF)
 #define PinConfigPin(config)           (((config) >> 0) & 0x3F)
 
-extern uint32_t SystemCoreClock;
-
 /*
  *  ======== getDutyCounts ========
  */
@@ -163,10 +161,7 @@ static uint32_t getDutyCounts(PWM_Duty_Units dutyUnits, uint32_t dutyValue,
     uint32_t      duty = 0;
     ClockP_FreqHz freq;
 
-    freq.hi = 0;
-    freq.lo = SystemCoreClock;
-
-    //ClockP_getCpuFreq(&freq);
+    ClockP_getCpuFreq(&freq);
 
     switch (dutyUnits) {
         case PWM_DUTY_COUNTS:
@@ -199,10 +194,7 @@ static uint32_t getPeriodCounts(PWM_Period_Units periodUnits,
     uint32_t      period = 0;
     ClockP_FreqHz freq;
 
-    freq.hi = 0;
-    freq.lo = SystemCoreClock;
-
-    //ClockP_getCpuFreq(&freq);
+    ClockP_getCpuFreq(&freq);
 
     switch (periodUnits) {
         case PWM_PERIOD_COUNTS: