hw/rtc/ls7a_rtc: Remove unimplemented device in realized function

Remove the unimplemented device when realized ls7a RTC, as it is not uesd.

Signed-off-by: Xiaojuan Yang <yangxiaojuan@loongson.cn>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220701093407.2150607-4-yangxiaojuan@loongson.cn>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

hw/rtc/ls7a_rtc.c

@@ -461,7 +461,6 @@ static void ls7a_rtc_realize(DeviceState *dev, Error **errp)
     d->save_toy_year = 0;
     d->save_rtc = 0;
 
-    create_unimplemented_device("mmio fallback 1", 0x10013ffc, 0x4);
 }
 
 static int ls7a_rtc_pre_save(void *opaque)