ALSA: usb-audio: fix uac control query argument

This patch fixes code readability and should have no functional change.

Correct uac control query functions to account for the 1-based indexing
of USB Audio Class control identifiers.

The function parameter, u8 control, should be the
constant defined in audio-v2.h to identify the control to be checked for
readability or writeability.

This patch fixes all callers that had adjusted, and makes explicit
the mapping between audio_feature_info[] array index and the associated
control identifier.

Signed-off-by: Andrew Chant <achant@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>