drm_hwcomposer: Set DPMS ON when setting active config

Ensure we turn the connector on after we set the active mode.

BUG=chrome-os-partner:41682
TEST=Tested on smaug with DP

Change-Id: I3410a1ac261fb0848d668c5baef2d77eb860017b
Signed-off-by: Sean Paul <seanpaul@chromium.org>
diff --git a/hwcomposer.cpp b/hwcomposer.cpp
index 3d39f6e..efc9b95 100644
--- a/hwcomposer.cpp
+++ b/hwcomposer.cpp
@@ -758,6 +758,11 @@
     ALOGE("Failed to set active config %d", ret);
     return ret;
   }
+  ret = ctx->drm.SetDpmsMode(display, DRM_MODE_DPMS_ON);
+  if (ret) {
+    ALOGE("Failed to set dpms mode on %d", ret);
+    return ret;
+  }
   return ret;
 }