libobs: Move macro to internal C file

Modifying this value would cause the entire project to recompile when
it's only used in one file in the first place.

libobs/media-io/media-io-defs.h

@@ -18,7 +18,3 @@
 #pragma once
 
 #define MAX_AV_PLANES 8
-
-/* time threshold in nanoseconds to ensure audio timing is as seamless as
- * possible */
-#define TS_SMOOTHING_THRESHOLD 70000000ULL

libobs/obs-source.c

@@ -1062,6 +1062,10 @@ static inline size_t conv_time_to_frames(const size_t sample_rate,
 /* maximum buffer size */
 #define MAX_BUF_SIZE        (1000 * AUDIO_OUTPUT_FRAMES * sizeof(float))
 
+/* time threshold in nanoseconds to ensure audio timing is as seamless as
+ * possible */
+#define TS_SMOOTHING_THRESHOLD 70000000ULL
+
 static inline void reset_audio_timing(obs_source_t *source, uint64_t timestamp,
 		uint64_t os_time)
 {