intel_idle: correct BXT support

intel_idle: correct BXT support

Orabug: 24810432

Commit 5dcef69486 ("intel_idle: add BXT support") added an 8-element
lookup array with just a 2-bit value used for lookups. As per the SDM
that bit field is really 3 bits wide. While this is supposedly benign
here, future re-use of the code for other CPUs might expose the issue.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
(cherry picked from commit bef450962597ff39a7f9d53a30523aae9eb55843)
Signed-off-by: Brian Maly <brian.maly@oracle.com>