rknn-toolkit & rknn-api for Toybrick

我烧了最新的固件TB-RK1808M0--image_V2.1，可以运行yolov5
D RKNNAPI: ==============================================
D RKNNAPI: RKNN VERSION:
D RKNNAPI:   API: 1.4.0 (bbe0dfc build: 2020-09-14 14:06:05)
D RKNNAPI:   DRV: 1.5.0 (83d70a9 build: 2020-09-30 16:25:49)
D RKNNAPI: ==============================================
rknn_init successed!