hwmon: (dell-smm) Blacklist Dell Studio XPS 8100

CPU fan speed going up and down on Dell Studio XPS 8100 for
unknown reasons. Without further debugging on the affected
machine, it is not possible to find the problem.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=100121
Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Tested-by: Jan C Peters <jcpeters89@gmail.com>
Cc: stable@vger.kernel.org # v4.0+, will need backport
[groeck: cleaned up description, comments]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>