[ALSA] Fix snd-usb-audio dependency on snd-hwdep.

USB
Signed-off-by: NJames Courtier-Dutton <James@superbug.co.uk>

sound/usb/Kconfig

@@ -6,6 +6,7 @@ menu "USB devices"
 config SND_USB_AUDIO
 	tristate "USB Audio/MIDI driver"
 	depends on SND && USB
+	select SND_HWDEP
 	select SND_RAWMIDI
 	select SND_PCM
 	help