[Settings] HW keys tweaks

(cherry picked from commit 9013a1128e2877f90f9e0246cfac369da158868f)

Conflicts:
	res/values/cr_strings.xml
	src/com/android/settings/ButtonSettings.java

Change-Id: I6fc33a7e729617d02824bd7a3161bc17e7d5f399

(cherry picked from commit 1be00f86c6acf2297aba2ffdfc4c87af33dae262)
settings: Add PerformanceControl [1/2]

Change-Id: I06b0815208041dd00f34ce01ca6b468cf54d26dd

Conflicts:
	res/values/cmr_strings.xml

(cherry picked from commit 556a64829bc02fb5b14e4dfb846b85774082adad)