We want to support attr->set callbacks that may need psmouse->state to
not be updated, or may want to manually deal w/ enabling and disabling
the device.  To do that, we create __PSMOUSE_DEFINE_ATTR which enables
us to set a 'protect' argument specifying whether or not the set
callback should be protected with psmouse_disable and state setting.
Signed-off-by: Andres Salomon <dilinger@debian.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>