Bluetooth: btusb: fix non-atomic allocation in completion handler

Bluetooth: btusb: fix non-atomic allocation in completion handler

BugLink: https://bugs.launchpad.net/bugs/1861784
commit 22cc6b7a1dbb58da4afc539d9b7d470b23a25eea upstream.

USB completion handlers are called in atomic context and must
specifically not allocate memory using GFP_KERNEL.

Fixes: a1c49c434e15 ("Bluetooth: btusb: Add protocol support for MediaTek MT7668U USB devices")
Cc: stable <stable@vger.kernel.org>     # 5.3
Cc: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>