pcm/*: add "noexcept"

src/pcm/PcmConvert.hxx

@@ -51,8 +51,8 @@ class PcmConvert {
 	bool enable_resampler, enable_format, enable_channels;
 
 public:
-	PcmConvert();
-	~PcmConvert();
+	PcmConvert() noexcept;
+	~PcmConvert() noexcept;
 
 	/**
 	 * Prepare the object.  Call Close() when done.
@@ -65,12 +65,12 @@ public:
 	 * Close the object after it was prepared with Open().  After
 	 * that, it may be reused by calling Open() again.
 	 */
-	void Close();
+	void Close() noexcept;
 
 	/**
 	 * Reset the filter's state, e.g. drop/flush buffers.
 	 */
-	void Reset();
+	void Reset() noexcept;
 
 	/**
 	 * Converts PCM data between two audio formats.