net/usb/usbnet: Convert timers to use timer_setup()

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly. Since the callback is called from
both a timer and a tasklet, adjust the tasklet to pass the timer address
too. When tasklets have their .data field removed, this can be refactored
to call a central function after resolving the correct container_of() for a
separate callback function for timer and tasklet.

Cc: Oliver Neukum <oneukum@suse.com>
Cc: netdev@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>