Silence maybe-uninitialized compiler warnings.

av1/decoder/decodeframe.c

diff --git a/av1/decoder/decodeframe.c b/av1/decoder/decodeframe.c
index 356d8cf..3aa866c 100644
--- a/av1/decoder/decodeframe.c
+++ b/av1/decoder/decodeframe.c
@@ -6697,7 +6697,7 @@
           continue;
         }
       }
-      bool qm_8x8_is_symmetric;
+      bool qm_8x8_is_symmetric = false;
       if (tsize == TX_8X8) {
         qm_8x8_is_symmetric = aom_rb_read_bit(rb);
       } else if (tsize == TX_4X8) {

av1/encoder/pickrst.c

diff --git a/av1/encoder/pickrst.c b/av1/encoder/pickrst.c
index bd7e230..d1ab6e7 100644
--- a/av1/encoder/pickrst.c
+++ b/av1/encoder/pickrst.c
@@ -1434,8 +1434,8 @@
           nsfilter_params->nsfilter_config.asymmetric2 ==
       0)
     return 0;
-  double sym_A[WIENERNS_A_SIZE];
-  double sym_b[WIENERNS_b_SIZE];
+  double sym_A[WIENERNS_A_SIZE] = { 0 };
+  double sym_b[WIENERNS_b_SIZE] = { 0 };
   int stridep = n;
   int ip = 0;
   for (int i = 0; i < n; ++i) {
@@ -1537,8 +1537,8 @@
     int n, const int *select, const double *A, int stride, const double *b,
     double *tmpbuf, int16_t *nsfilter,
     const WienernsFilterParameters *nsfilter_params) {
-  double sel_A[WIENERNS_A_SIZE];
-  double sel_b[WIENERNS_b_SIZE];
+  double sel_A[WIENERNS_A_SIZE] = { 0 };
+  double sel_b[WIENERNS_b_SIZE] = { 0 };
   int stridep = n;
   int ip = 0;
   for (int i = 0; i < n; ++i) {
@@ -1600,8 +1600,8 @@
           nsfilter_params->nsfilter_config.asymmetric2 ==
       0)
     return 0;
-  double sym_A[WIENERNS_A_SIZE];
-  double sym_b[WIENERNS_b_SIZE];
+  double sym_A[WIENERNS_A_SIZE] = { 0 };
+  double sym_b[WIENERNS_b_SIZE] = { 0 };
   int stridep = n;
   int ip = 0;
   for (int i = 0; i < n; ++i) {