aom_dsp,x86: rename sad_highbd_avx2.c -> highbd_sad_avx2.c

highbd_* is used for all other x86 files under this tree

Change-Id: Ib19e460a7d308063861f12972590856927a0ae22
diff --git a/aom_dsp/aom_dsp.cmake b/aom_dsp/aom_dsp.cmake
index 272272b..4e43a37 100644
--- a/aom_dsp/aom_dsp.cmake
+++ b/aom_dsp/aom_dsp.cmake
@@ -254,7 +254,7 @@
               "${AOM_ROOT}/aom_dsp/x86/highbd_adaptive_quantize_avx2.c"
               "${AOM_ROOT}/aom_dsp/x86/sad4d_avx2.c"
               "${AOM_ROOT}/aom_dsp/x86/sad_avx2.c"
-              "${AOM_ROOT}/aom_dsp/x86/sad_highbd_avx2.c"
+              "${AOM_ROOT}/aom_dsp/x86/highbd_sad_avx2.c"
               "${AOM_ROOT}/aom_dsp/x86/sad_impl_avx2.c"
               "${AOM_ROOT}/aom_dsp/x86/variance_avx2.c"
               "${AOM_ROOT}/aom_dsp/x86/highbd_variance_avx2.c"
diff --git a/aom_dsp/x86/sad_highbd_avx2.c b/aom_dsp/x86/highbd_sad_avx2.c
similarity index 100%
rename from aom_dsp/x86/sad_highbd_avx2.c
rename to aom_dsp/x86/highbd_sad_avx2.c