Merge pull request ARMmbed#91 from linlingao/fix_rtc_init

Fixed a bug in soft reset where RTC is not enabled after soft reset

Author: linlingao

targets/TARGET_TI/TARGET_CC32XX/TARGET_CC3220SF/rtc_api.c

@@ -24,7 +24,10 @@ void rtc_init(void) {
     static bool rtc_initialized = false;
     if (!rtc_initialized)
     {
-        PRCMRTCInUseSet();
+        if (!PRCMRTCInUseGet)
+        {
+            PRCMRTCInUseSet();
+        }
         rtc_initialized = true;
     }
 }

targets/TARGET_TI/TARGET_CC32XX/TARGET_CC3220SF/ti/devices/cc32xx/driverlib/prcm.c

@@ -1988,10 +1988,8 @@ void PRCMCC3200MCUInit()
     //
     // Enable RTC
     //
-    if(PRCMSysResetCauseGet()== PRCM_POWER_ON)
-    {
-        PRCMHIBRegWrite(0x4402F804,0x1);
-    }
+
+    PRCMHIBRegWrite(0x4402F804,0x1);
 
     //
     // Enable Timers