display: Add BufferMirrorMode support for External

- In Buffer mirror mode, the output on the external should be rotated
  based on the primary orientation.
- this is used for the side sync feature.
- buffermirrormode has higher precedence over external orientation
- Add binder interface to enable/disable buffermirror mode

Change-Id: Ibea0af9627d69b4d42453adc868b113d82613437
diff --git a/libhwcomposer/hwc_qclient.cpp b/libhwcomposer/hwc_qclient.cpp
index c20f5c1..5d7d4d3 100644
--- a/libhwcomposer/hwc_qclient.cpp
+++ b/libhwcomposer/hwc_qclient.cpp
@@ -64,6 +64,9 @@
         case IQService::EXTERNAL_ORIENTATION:
             setExtOrientation(value);
             break;
+        case IQService::BUFFER_MIRRORMODE:
+            setBufferMirrorMode(value);
+            break;
         default:
             return NO_ERROR;
     }
@@ -118,4 +121,8 @@
     mHwcContext->mExtOrientation = orientation;
 }
 
+void QClient::setBufferMirrorMode(uint32_t enable) {
+    mHwcContext->mBufferMirrorMode = enable;
+}
+
 }