pm: cpupower: bindings: Improve disable c_state block

This commit fixes a bad comment, removes an unneeded code block, and
catches a few more states that cpuidle_state_disable with the test
script. Part of the motivation for this commit was I kept forgetting to
use sudo.

Signed-off-by: "John B. Wyatt IV" <jwyatt@redhat.com>
Signed-off-by: "John B. Wyatt IV" <sageofredondo@gmail.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>