ALSA: us122l - Add missing dependency on CONFIG_SND_HWDEP

CONFIG_SND_USB_US122L uses snd_hwdep_new(), so SND_HWDEP needs
to be enabled (selected).

ERROR: "snd_hwdep_new" [sound/usb/usx2y/snd-usb-us122l.ko] undefined!

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>