[TOPI] Update pre-tuned parameters for TX2 and fp16 on Mali (#1892)

apps/benchmark/README.md

apps/benchmark/arm_cpu_imagenet_bench.py

apps/benchmark/gpu_imagenet_bench.py

apps/benchmark/mobile_gpu_imagenet_bench.py

apps/benchmark/util.py

python/tvm/autotvm/measure/executor.py

python/tvm/autotvm/tophub.py

python/tvm/exec/autotvm_log_editor.py

topi/python/topi/mali/conv2d.py

tutorials/autotvm/tune_nnvm_arm.py

tutorials/autotvm/tune_nnvm_cuda.py

tutorials/autotvm/tune_nnvm_mobile_gpu.py