usb: usbatm: 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. Additionally corrects and on-stack
timer usage.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Duncan Sands <duncan.sands@free.fr>
Cc: "Gustavo A. R. Silva" <garsilva@embeddedor.com>
Cc: accessrunner-general@lists.sourceforge.net
Cc: linux-usb@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Allen Pais <allen.lkml@gmail.com>