shell/sc_rtc: remove rtc init command

sys/shell/commands/sc_rtc.c

@@ -139,7 +139,6 @@ static int _rtc_usage(void)
 {
     puts("usage: rtc <command> [arguments]");
     puts("commands:");
-    puts("\tinit\t\tinitialize the interface");
     puts("\tpoweron\t\tpower the interface on");
     puts("\tpoweroff\tpower the interface off");
     puts("\tclearalarm\tdeactivate the current alarm");
@@ -156,9 +155,6 @@ int _rtc_handler(int argc, char **argv)
         _rtc_usage();
         return 1;
     }
-    else if (strncmp(argv[1], "init", 4) == 0) {
-        rtc_init();
-    }
     else if (strncmp(argv[1], "poweron", 7) == 0) {
         rtc_poweron();
     }