drm_hwcomposer: Fix GetDisplayIdentificationData

Fix GetDisplayIdentificationData, introduced
by commit: b3d817815fad.
Edid data should be copied instead of assign.

Signed-off-by: Andrii Chepurnyi <andrii_chepurnyi@epam.com>
diff --git a/drmhwctwo.cpp b/drmhwctwo.cpp
index 605406b..798e013 100644
--- a/drmhwctwo.cpp
+++ b/drmhwctwo.cpp
@@ -997,10 +997,13 @@
 
   blob = drmModeGetPropertyBlob(drm_->fd(), blob_id);
 
-  outData = static_cast<uint8_t *>(blob->data);
-
+  if (outData) {
+    *outDataSize = std::min(*outDataSize, blob->length);
+    memcpy(outData, blob->data, *outDataSize);
+  } else {
+    *outDataSize = blob->length;
+  }
   *outPort = connector_->id();
-  *outDataSize = blob->length;
 
   return HWC2::Error::None;
 }