[ALSA] sound: hdspm.c fix returning void expression warnings

Just drop the returns.
sound/pci/rme9652/hdspm.c:1031:3: warning: returning void-valued expression
sound/pci/rme9652/hdspm.c:1033:3: warning: returning void-valued expression
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/rme9652/hdspm.c

@@ -1028,9 +1028,9 @@ static inline void snd_hdspm_midi_write_byte (struct hdspm *hdspm, int id,
 {
 	/* the hardware already does the relevant bit-mask with 0xff */
 	if (id)
-		return hdspm_write(hdspm, HDSPM_midiDataOut1, val);
+		hdspm_write(hdspm, HDSPM_midiDataOut1, val);
 	else
-		return hdspm_write(hdspm, HDSPM_midiDataOut0, val);
+		hdspm_write(hdspm, HDSPM_midiDataOut0, val);
 }
 
 static inline int snd_hdspm_midi_input_available (struct hdspm *hdspm, int id)