ffplay: set type for channel_layout AudioParams field to int64_t

Reflect the type of the corresponding field in lavc/lavfi.

ffplay.c

@@ -139,7 +139,7 @@ typedef struct SubPicture {
 typedef struct AudioParams {
     int freq;
     int channels;
-    int channel_layout;
+    int64_t channel_layout;
     enum AVSampleFormat fmt;
 } AudioParams;