avcodec/g723_1enc: Make min_err 64bit

This is intending to fix the case described in https://lists.ffmpeg.org/archives/list/ffmpeg-devel@ffmpeg.org/thread/AAZ7GJPPUJI5SCVTDGJ6QL7UUEP56WOM/
Where FCBParam optim is used uninitialized

a min_err of 1<<30, allows the struct to be never initilialized as all
err (which is int32_t) can be larger than min_err. By increasing min_err
above the int32_t range this is no longer possible

Untested, as i do not have the testcase

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>i
(cherry picked from commit 909af3a571da830cc70a34f0c3946379bd12dfbe)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/g723_1.h

@@ -108,7 +108,7 @@ typedef struct HFParam {
  * Optimized fixed codebook excitation parameters
  */
 typedef struct FCBParam {
-    int min_err;
+    int64_t min_err;
     int amp_index;
     int grid_index;
     int dirac_train;

libavcodec/g723_1enc.c

@@ -1013,7 +1013,7 @@ static void fcb_search(G723_1_ChannelContext *p, int16_t *impulse_resp,
     int pulse_cnt = pulses[index];
     int i;
 
-    optim.min_err = 1 << 30;
+    optim.min_err = 1LL << 31;
     get_fcb_param(&optim, impulse_resp, buf, pulse_cnt, SUBFRAME_LEN);
 
     if (p->pitch_lag[index >> 1] < SUBFRAME_LEN - 2) {