wmalosslessdec: fix mclms_coeffs* array size

Fixes corruption of context

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC:libav-stable@libav.org
Bug-Id: CVE-2014-2098
Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavcodec/wmalosslessdec.c

@@ -129,8 +129,8 @@ typedef struct WmallDecodeCtx {
 
     int8_t  mclms_order;
     int8_t  mclms_scaling;
-    int16_t mclms_coeffs[128];
-    int16_t mclms_coeffs_cur[4];
+    int16_t mclms_coeffs[WMALL_MAX_CHANNELS * WMALL_MAX_CHANNELS * 32];
+    int16_t mclms_coeffs_cur[WMALL_MAX_CHANNELS * WMALL_MAX_CHANNELS];
     int16_t mclms_prevvalues[WMALL_MAX_CHANNELS * 2 * 32];
     int16_t mclms_updates[WMALL_MAX_CHANNELS * 2 * 32];
     int     mclms_recent;