BugLink: https://bugs.launchpad.net/bugs/1859865

commit 2438c3a1 upstream.

Telit FN980 flashing device 0x1bc7/0x9010 requires zero packet
to be sent if out data size is is equal to the endpoint max size.
Signed-off-by: Daniele Palmas <dnlplm@gmail.com>
[ johan: switch operands in conditional ]
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>