ALSA: usb-audio: Add missing kconfig dependecy

commit 4fa71c1550a857ff1dbfe9e99acc1f4cfec5f0d0 upstream.

The commit 44dcbbb1 introduced the usage of bitreverse helpers but
forgot to add the dependency.  This patch adds the selection for
CONFIG_BITREVERSE.

Fixes: 44dcbbb1 ('ALSA: snd-usb: add support for bit-reversed byte formats')
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>