ALSA: usb-audio: use a format bitmask per alternate setting

In preparation for USB audio 2.0 support, change the audioformat
structure so that it uses a bitmask to specify possible formats.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
8 files changed