CtsGraphicsTestCases: increase timeout in CameraGpuTest

Increase timeout for finishing rendering of 100 frames in CameraGpuTest.
The embedded devices are not fast enough to draw them within 10 seconds
because of the low performance CPU and no GPU on the board.

Bug: 63106979
Test: android.graphics.cts.CameraGpuTest#\
      testCameraImageCaptureAndRendering on imx7d
Change-Id: I592dabda528f96e62aa6c4d345ffe4cf868bf592
diff --git a/tests/tests/graphics/src/android/graphics/cts/CameraGpuCtsActivity.java b/tests/tests/graphics/src/android/graphics/cts/CameraGpuCtsActivity.java
index b743e7d..466912a 100644
--- a/tests/tests/graphics/src/android/graphics/cts/CameraGpuCtsActivity.java
+++ b/tests/tests/graphics/src/android/graphics/cts/CameraGpuCtsActivity.java
@@ -93,7 +93,7 @@
 
     public void waitToFinishRendering() throws InterruptedException {
         // Wait long enough so that all frames are captured.
-        if (!mFinishedRendering.await(10, TimeUnit.SECONDS)) {
+        if (!mFinishedRendering.await(30, TimeUnit.SECONDS)) {
             throw new IllegalStateException("Coudn't finish drawing frames!");
         }
     }