sound: usb-audio: handle wMaxPacketSize for FIXED_ENDPOINT devices

sound: usb-audio: handle wMaxPacketSize for FIXED_ENDPOINT devices

commit 894dcd78782842924527598b0b764c9b4e679e21 upstream.

For audio devices that do not have proper audio descriptors (e.g.,
Edirol UA-20), we use hardcoded parameters from our quirks list.
However, we must still read the maximum packet size from the standard
endpoint descriptor; otherwise, we might use packets that are too big
and therefore rejected by the USB core.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>