ImageReader: fix the 0 crop rect size issue

Rect isValid actually include the zero size case, which we don't want to include
in our case. This causes camera ImageReader test case fails at buffer size
sanity check.

Bug: 9802344
Change-Id: I561f5a049c6117c613df1e1b2789c43af9a19628
diff --git a/media/jni/android_media_ImageReader.cpp b/media/jni/android_media_ImageReader.cpp
index fb0f69b..a03dbf3 100644
--- a/media/jni/android_media_ImageReader.cpp
+++ b/media/jni/android_media_ImageReader.cpp
@@ -737,7 +737,7 @@
     int outputHeight = buffer->height;
 
     // Correct width/height when crop is set.
-    if (buffer->crop.isValid()) {
+    if (!buffer->crop.isEmpty()) {
         outputWidth = buffer->crop.getWidth();
         outputHeight = buffer->crop.getHeight();
     }