qdm2: avoid integer overflow

CC: libav-stable@libav.org
Bug-Id: CID 700555
(cherry picked from commit 1f80742f49)
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

libavcodec/qdm2.c

@@ -730,7 +730,7 @@ static void fill_coding_method_array(sb_int8_array tone_level_idx,
                     for (j = 0; j < 64; j++)
                         acc += tone_level_idx_temp[ch][sb][j];
 
-            multres = 0x66666667 * (acc * 10);
+            multres = 0x66666667LL * (acc * 10);
             esp_40 = (multres >> 32) / 8 + ((multres & 0xffffffff) >> 31);
             for (ch = 0;  ch < nb_channels; ch++)
                 for (sb = 0; sb < 30; sb++)