histogram: disable HWC sampling functions.

Disable the function pointers after porting the sampling functions
during the rest of the port. All histogram code is latent/unused.

cherry pick from hardware/qcom/sm8150/display

Bug: 143513619
Test: ./color_sampling_test
Test: libgui_test  --gtest_filter=DisplayedContentSamplingTest*
Test: dumpsys SurfaceFlinger

Change-Id: I493d38fe4bc1d33f2bd709fdfc2ebb86475007c1
1 file changed