avcodec/apedec: use av_fast_padded_malloc()

Fixes use of uninitialized memory
Fixes part of msan_uninit-mem_7fa0d8c8bd58_8417_sh3.ape
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/apedec.c

@@ -1438,7 +1438,7 @@ static int ape_decode_frame(AVCodecContext *avctx, void *data,
         }
         if (s->fileversion < 3950) // previous versions overread two bytes
             buf_size += 2;
-        av_fast_malloc(&s->data, &s->data_size, buf_size);
+        av_fast_padded_malloc(&s->data, &s->data_size, buf_size);
         if (!s->data)
             return AVERROR(ENOMEM);
         s->dsp.bswap_buf((uint32_t*)s->data, (const uint32_t*)buf, buf_size >> 2);