Revert "PowerManagerService: enable logging for when mPowerState changes."

This reverts commit 24ace3395b532e3cbb63d2a6197a91dd9242bb36.

Bug b/2265538 (verbose logging from power manager)
diff --git a/services/java/com/android/server/PowerManagerService.java b/services/java/com/android/server/PowerManagerService.java
index 38269e1..94cf6d4 100644
--- a/services/java/com/android/server/PowerManagerService.java
+++ b/services/java/com/android/server/PowerManagerService.java
@@ -1403,7 +1403,7 @@
             boolean oldScreenOn = (mPowerState & SCREEN_ON_BIT) != 0;
             boolean newScreenOn = (newState & SCREEN_ON_BIT) != 0;
 
-            if (mPowerState != newState) {
+            if (mSpew) {
                 Log.d(TAG, "setPowerState: mPowerState=" + mPowerState
                         + " newState=" + newState + " noChangeLights=" + noChangeLights);
                 Log.d(TAG, "  oldKeyboardBright=" + ((mPowerState & KEYBOARD_BRIGHT_BIT) != 0)