avcodec/takdec: Skip last p2 sample (which is unused)

Fixes out of array read
Fixes: cb3f38b08b4541523974667c7d1eee9e/asan_heap-oob_2659e18_9838_021fd5cd635bf76cede6398cd9ecbcdd.tak

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/takdec.c

@@ -621,7 +621,7 @@ static int decorrelate(TAKDecContext *s, int c1, int c2, int length)
         for (; length2 > 0; length2 -= tmp) {
             tmp = FFMIN(length2, x);
 
-            for (i = 0; i < tmp; i++)
+            for (i = 0; i < tmp - (tmp == length2); i++)
                 s->residues[filter_order + i] = *p2++ >> dshift;
 
             for (i = 0; i < tmp; i++) {