Halts the clock supplied to the real-time clock.
Remark 
1. Calling 
this API function changes the real-time clock to reset status.
For 
this reason, writes to the control registers after this API function is called 
are ignored.
Remark 
2. This API 
function stops the clock supply to the real-time clock, by operating the RTCEN 
bit of peripheral enable register n.
For this reason, this API 
function also stops the clock supply to other peripheral devices sharing the 
RTCEN bit (e.g. interval timer).
[Syntax]
void R_RTC_Set_PowerOff ( void );
[Argument(s)]
None.
[Return value]
None.