aom_dsp/x86/intrapred_avx2: fix int sanitizer warnings

 implicit conversion from type 'int' of value 32820 (32-bit, signed) to
 type 'short' changed the value to -32716 (16-bit, signed)

 BUG=aomedia:2357

Change-Id: I08714538309dac8d01057c78642be9a5224c6ecd

aom_dsp/x86/intrapred_avx2.c

diff --git a/aom_dsp/x86/intrapred_avx2.c b/aom_dsp/x86/intrapred_avx2.c
index 69adb9e..aae8173 100644
--- a/aom_dsp/x86/intrapred_avx2.c
+++ b/aom_dsp/x86/intrapred_avx2.c
@@ -2758,7 +2758,7 @@
     __m256i resxy, j256, r6;
     __m128i a0_x128, a1_x128, a0_1_x128, a1_1_x128;
     int y = r + 1;
-    ydx = _mm256_set1_epi16(y * dx);
+    ydx = _mm256_set1_epi16((short)(y * dx));
 
     for (int j = 0; j < W; j += 16) {
       j256 = _mm256_set1_epi16(j);
@@ -4210,10 +4210,10 @@
         mask256 = _mm256_cmpgt_epi16(min_base_y256, base_y_c256);
 
         base_y_c256 = _mm256_blendv_epi8(base_y_c256, min_base_y256, mask256);
-        int16_t min_y =
-            _mm_extract_epi16(_mm256_extracti128_si256(base_y_c256, 1), 7);
+        int16_t min_y = (int16_t)_mm_extract_epi16(
+            _mm256_extracti128_si256(base_y_c256, 1), 7);
         int16_t max_y =
-            _mm_extract_epi16(_mm256_castsi256_si128(base_y_c256), 0);
+            (int16_t)_mm_extract_epi16(_mm256_castsi256_si128(base_y_c256), 0);
         int16_t offset_diff = max_y - min_y;
 
         if (offset_diff < 16) {