ALSA: usb-audio: Move generic DSD raw detection into quirk_flags

The generic DSD raw detection is based on the known allow list, and we
can integrate it into quirk_flags, too.

Link: https://lore.kernel.org/r/20210729074404.19728-4-tiwai@suse.de


Signed-off-by: Takashi Iwai <tiwai@suse.de>