Bluetooth: btusb: handle mSBC audio over USB Endpoints

For mSBC encoded audio stream over usb transport, btusb driver
to be set to alternate settings 6 as per BT core spec 5.0. The
type of air mode is used to differenting which alt setting to be
used.

The changes are made considering some discussion over the similar
patch submitted earlier from Kuba Pawlak (link below)
https://www.spinics.net/lists/linux-bluetooth/msg64577.html

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Sathish Narasimman <sathish.narasimman@intel.com>
Signed-off-by: Chethan T N <chethan.tumkur.narayan@intel.com>
Signed-off-by: Hsin-Yu Chao <hychao@chromium.org>
Signed-off-by: Amit K Bag <amit.k.bag@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>