ACPI: Allow overriding to higher critical trip point.

ACPI: Allow overriding to higher critical trip point.

http://bugzilla.kernel.org/show_bug.cgi?id=9129

lenb: Note that overriding a critical trip point
may simply fool the user into thinking that they
have control that they do not actually have.
For it is EC firmware that decides when the EC
sends Linux temperature change events, and the
EC may or may not decide to send Linux these events
anywhere in the neighborhood of the fake
override trip points.  Beware.

note also that thermal.nocrt is already available
to disable crtical trip point actios,
and thermal.crt=-1 is already available to
disabled critical trip points entirely.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>