ALSA: usb-audio: replace hardcoded value with const

In this context, 0x01 is USB_ENDPOINT_XFER_ISOC.

Signed-off-by: Eldad Zack <eldad@fogrefinery.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 7c64b95..f488a49 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -384,7 +384,7 @@
 		/* ... and check descriptor size before accessing bSynchAddress
 		   because there is a version of the SB Audigy 2 NX firmware lacking
 		   the audio fields in the endpoint descriptors */
-		if ((get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) != 0x01 ||
+		if ((get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) != USB_ENDPOINT_XFER_ISOC ||
 		    (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
 		     get_endpoint(alts, 1)->bSynchAddress != 0 &&
 		     !implicit_fb)) {