sound: usb: Find alt setting using format and service interval

Audio device supporting burst mode exposes alt settings with
different service intervals. In order to find the requested
format as well as service interval remote entity provides
service interval parameter. Data interval (bInterval - 1) is
calculated using service interval and used to find the matching
alt setting using find_format_and_si().

Change-Id: Ie15c78ab53eb5258085b54bf13459ebef44a44a4
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>