update resnet18_bf16 tutorial for v6.2#11

AlphaBu wants to merge 2 commits into

amd:release/6.2amd/Vitis-AI:release/6.2from

AlphaBu:release_6.2_resnet18_bf16AlphaBu/Vitis-AI:release_6.2_resnet18_bf16Copy head branch name to clipboard