掌機 - FC3000 - 解決undefined reference to __atomic_load_8問題

參考資訊：
https://github.com/alexa/avs-device-sdk/issues/1404

問題如下：

<artificial>:(.text+0x9cf8): undefined reference to `__atomic_load_8'
<artificial>:(.text+0x9d38): undefined reference to `__atomic_compare_exchange_8'

解法如下：

LDFLAGS += -latomic