remove ":arm" to build tflite on ARM64 linux

When build TF Lite related stuff such as lable_image for tflite on
ARMv64 non-Android environment (I am running Debian on an internal
development board). I saw something like:

  /home/freedom/work/tensorflow/tensorflow/contrib/lite/kernels/internal/BUILD:264:1: C++ compilation of rule '//tensorflow/contrib/lite/kernels/internal:neon_tensor_utils' failed (Exit 1)
  gcc: error: unrecognized command line option '-mfpu=neon'

It seems ARM64 falls into this ":arm" category. After removing it, I can
build my tflite-based command line programs without problems.