ALSA: line6: Drop MISSING_CASE macro

Such a debug is needed in the core code, not in each lowlevel driver.
Tested-by: Chris Rorvick <chris@rorvick.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/line6/driver.h

@@ -48,10 +48,6 @@
 
 #define LINE6_CHANNEL_MASK 0x0f
 
-#define MISSING_CASE	\
-	pr_err("line6usb driver bug: missing case in %s:%d\n", \
-		__FILE__, __LINE__)
-
 #define CHECK_RETURN(x)		\
 do {				\
 	err = x;		\

sound/usb/line6/pcm.c

@@ -488,9 +488,6 @@ int snd_line6_prepare(struct snd_pcm_substream *substream)
 			line6_unlink_wait_clear_audio_in_urbs(line6pcm);
 
 		break;
-
-	default:
-		MISSING_CASE;
 	}
 
 	if (!test_and_set_bit(LINE6_INDEX_PREPARED, &line6pcm->flags)) {