samplefmt: avoid integer overflow in av_samples_get_buffer_size()

CC:libav-stable@libav.org
(cherry picked from commit 0e830094ad)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavutil/samplefmt.c

@@ -135,6 +135,8 @@ int av_samples_get_buffer_size(int *linesize, int nb_channels, int nb_samples,
 
     /* auto-select alignment if not specified */
     if (!align) {
+        if (nb_samples > INT_MAX - 31)
+            return AVERROR(EINVAL);
         align = 1;
         nb_samples = FFALIGN(nb_samples, 32);
     }