Fix high bit depth build in cmake.

Fix the mistyped variable name that smashed a source list.

Change-Id: Id654ec06d2a1c479de5f61bb8c48e9e1df51086b
diff --git a/aom_dsp/aom_dsp.cmake b/aom_dsp/aom_dsp.cmake
index 17915ea..8f6f9bf 100644
--- a/aom_dsp/aom_dsp.cmake
+++ b/aom_dsp/aom_dsp.cmake
@@ -231,7 +231,7 @@
         "${AOM_ROOT}/aom_dsp/x86/highbd_variance_sse4.c")
 
     set(AOM_DSP_ENCODER_AVX2_INTRIN
-        ${AOM_ENCODER_DSP_AVX2_INTRIN}
+        ${AOM_DSP_ENCODER_AVX2_INTRIN}
         "${AOM_ROOT}/aom_dsp/x86/sad_highbd_avx2.c")
   endif ()