drm_hwcomposer: Fix another build warning in HwcDisplay::SetPowerMode()

Building with AOSP I see:

external/drm_hwcomposer/hwc2_device/HwcDisplay.cpp:768:50: warning: format specifies type 'int' but the argument has type 'HWC2::PowerMode' [-Wformat]
  768 |       ALOGE("Incorrect power mode value (%d)\n", mode);
      |                                          ~~      ^~~~
      |                                                  static_cast<int>(

So this patch tweaks the message to use integer mode_in argument
to the function.

Change-Id: I9211733137ad194d5040a1d497b008b4c2c491dd
Signed-off-by: John Stultz <jstultz@google.com>
diff --git a/hwc2_device/HwcDisplay.cpp b/hwc2_device/HwcDisplay.cpp
index c9d9a68..6f08c33 100644
--- a/hwc2_device/HwcDisplay.cpp
+++ b/hwc2_device/HwcDisplay.cpp
@@ -765,7 +765,7 @@
     case HWC2::PowerMode::DozeSuspend:
       return HWC2::Error::Unsupported;
     default:
-      ALOGE("Incorrect power mode value (%d)\n", mode);
+      ALOGE("Incorrect power mode value (%d)\n", mode_in);
       return HWC2::Error::BadParameter;
   }