cpuidle: lpm-levels: Suppress driver bind/unbind feature

LPM driver do not support bind/unbind using sysfs.
Set suppress bind attribute to disallow this.

Change-Id: If5719a89ed26ece88a8809f5a2b4aa30b3d98226
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>