Revert "Handle lock() returning a NULL buffer in SurfaceUtils."

This reverts commit afeffa81d06e7ca485f6d13430b8dfc70b4938a1.

Bug: 28526999

Change-Id: I18a073e92b516706c777f121a00d06938fdf35e3
diff --git a/media/libstagefright/SurfaceUtils.cpp b/media/libstagefright/SurfaceUtils.cpp
index 60ef662..568837a 100644
--- a/media/libstagefright/SurfaceUtils.cpp
+++ b/media/libstagefright/SurfaceUtils.cpp
@@ -186,10 +186,6 @@
             break;
         }
 
-        if (img == NULL) {
-            ALOGE("error pushing blank frames: lock returned NULL buffer");
-            break;
-        }
         *img = 0;
 
         err = buf->unlock();