avcodec/vvc/vvc_inter_template: Fix left shift of negative number

Affected the vvc-conformance-WP_A_3 FATE test.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/vvc/vvc_inter_template.c

@@ -46,7 +46,7 @@ static void FUNC(w_avg)(uint8_t *_dst, const ptrdiff_t _dst_stride,
     pixel *dst                  = (pixel*)_dst;
     const ptrdiff_t dst_stride  = _dst_stride / sizeof(pixel);
     const int shift             = denom + FFMAX(3, 15 - BIT_DEPTH);
-    const int offset            = (((o0 + o1) << (BIT_DEPTH - 8)) + 1) << (shift - 1);
+    const int offset            = ((o0 + o1) * (1 << (BIT_DEPTH - 8)) + 1) * (1 << (shift - 1));
 
     for (int y = 0; y < height; y++) {
         for (int x = 0; x < width; x++)