ALSA: usb-audio: fix CM6206 register definitions

fix typo after a recent commit causing headphones to have no sound

Fixes: ad43d528 (ALSA: usb-audio: Define registers for CM6206)
Signed-off-by: Amadeusz Sławiński <amade@asmblr.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/quirks.c

@@ -768,7 +768,7 @@ static int snd_usb_cm6206_boot_quirk(struct usb_device *dev)
 		 * REG1: PLL binary search enable, soft mute enable.
 		 */
 		CM6206_REG1_PLLBIN_EN |
-		CM6206_REG1_SOFT_MUTE_EN |
+		CM6206_REG1_SOFT_MUTE_EN,
 		/*
 		 * REG2: enable output drivers,
 		 * select front channels to the headphone output,