ALPS touchpad detection fails if some buttons of ALPS are pressed.
The reason is that the "E6" query response byte is different from
what is expected.

This was tested on a Toshiba Portege R500.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: NAkio Idehara <zbe64533@gmail.com>
Tested-by: NSeth Forshee <seth.forshee@canonical.com>
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>