ALSA: opl3: fix mismatch between snd_opl3_drum_switch definition and declaration

The function snd_opl3_drum_switch declaration in the header file
has the order of the two arguments on_off and vel swapped when
compared to the definition arguments of vel and on_off.  Fix this
by swapping them around to match the definition.

This error predates the git history, so no idea when this error
was introduced.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/drivers/opl3/opl3_voice.h

@@ -41,7 +41,7 @@ void snd_opl3_timer_func(struct timer_list *t);
 
 /* Prototypes for opl3_drums.c */
 void snd_opl3_load_drums(struct snd_opl3 *opl3);
-void snd_opl3_drum_switch(struct snd_opl3 *opl3, int note, int on_off, int vel, struct snd_midi_channel *chan);
+void snd_opl3_drum_switch(struct snd_opl3 *opl3, int note, int vel, int on_off, struct snd_midi_channel *chan);
 
 /* Prototypes for opl3_oss.c */
 #if IS_ENABLED(CONFIG_SND_SEQUENCER_OSS)