message: Fix a build error with Makefile
  Recent Densify op requires additional dependency.
  This change resolves
diff: @@ -110,6 +110,7 @@ $(wildcard tensorflow/lite/kernels/*.cc) \
  $(wildcard tensorflow/lite/kernels/internal/*.cc) \
  $(wildcard tensorflow/lite/kernels/internal/optimized/*.cc) \
  $(wildcard tensorflow/lite/kernels/internal/reference/*.cc) \
  +$(wildcard tensorflow/lite/tools/optimize/sparsity/*.cc) \
  $(PROFILER_SRCS) \
  tensorflow/lite/tools/make/downloads/farmhash/src/farmhash.cc \
  tensorflow/lite/tools/make/downloads/fft2d/fftsg.c \
  