Update chrome os light bar location

Recent modifications to the kernel have changed the location of the
sysfs entry that controls the light bar.  Update the light bar class
with the new location.

BUG=none
Signed-off-by: Chirantan Ekbote <chirantan@chromium.org>

Review URL: https://codereview.chromium.org/588293002

Cr-Commit-Position: refs/heads/master@{#296059}

chrome/browser/chromeos/power/light_bar.cc

@@ -18,7 +18,8 @@ namespace chromeos {
 namespace {
 const int kDarkSuspendDelaySeconds = 4;
 const char kLightBarControlPath[] =
-    "/sys/devices/virtual/chromeos/cros_ec/lightbar/sequence";
+    "/sys/devices/platform/cros_ec_lpc.0/cros-ec-dev.0/chromeos/cros_ec/"
+    "lightbar/sequence";
 const char kKonamiCommand[] = "KONAMI";
 
 }  // namespace