ALSA: usb-audio: fix Roland A-PRO support

commit 7da58046482fceb17c4a0d4afefd9507ec56de7f upstream.

The quirk for the Roland/Cakewalk A-PRO keyboards accidentally used the
wrong interface number, which prevented the driver from attaching to the
device.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>