ALSA: snd-usb: move code from urb.c to endpoint.c

No code altered at this point, simply preparing for upcoming
refactorizations.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Acked-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/Makefile b/sound/usb/Makefile
index 5390db0..ac256dc 100644
--- a/sound/usb/Makefile
+++ b/sound/usb/Makefile
@@ -12,8 +12,7 @@
 			pcm.o \
 			proc.o \
 			quirks.o \
-			stream.o \
-			urb.o
+			stream.o
 
 snd-usbmidi-lib-objs := midi.o