Refactor Opus decoder

Created generic playback handler, first with Opus support. Other
decoders to follow. This is to remove duplicated code.

3DSX tested working with citra and N3DS.

Signed-off-by: Mahyar Koshkouei <deltabeard@users.noreply.github.com>

source/all.h

@@ -4,9 +4,19 @@
 #define CHANNEL	0x08
 
 /* Adds extra debugging text */
-//#define DEBUG
+#define DEBUG
 
 /* Prints more error information */
 #define err_print(err) \
 	do { fprintf(stderr, "\nError %d:%s(): %s %s\n", __LINE__, __func__, \
 			err, strerror(errno)); } while (0)
+
+struct decoder_fn
+{
+	int (* init)(const char* file);
+	uint32_t (* rate)(void);
+	uint8_t channels;
+	int buffSize;
+	uint64_t (* decode)(void*);
+	void (* exit)(void);
+};