ALSA: usb-audio: Add native DSD support for TEAC 501/503 DAC

ALSA: usb-audio: Add native DSD support for TEAC 501/503 DAC

[ Upstream commit 7f38ca047b0cb54df7f6d9e4110e292e45dba6ad ]

This patch adds native DSD support for the following devices.

- TEAC NT-503
- TEAC UD-503
- TEAC UD-501

(1) Add quirks for native DSD support for TEAC devices.
(2) A specific vendor command is needed to switch between PCM/DOP and
    DSD mode, same as Denon/Marantz devices.

Signed-off-by: Nobutaka Okabe <nob77413@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>