Use correct gralloc flags in V4L2 Camera HAL

Also checks gralloc return results, and cleans up style.

BUG: https://b/31595935, https://b/31589070
TEST: test streaming app works
Change-Id: I4d910524ae21a7b666a1f456e2b7122a8671560f
diff --git a/modules/camera/3_4/v4l2_gralloc.h b/modules/camera/3_4/v4l2_gralloc.h
index 7ece59d..82129e3 100644
--- a/modules/camera/3_4/v4l2_gralloc.h
+++ b/modules/camera/3_4/v4l2_gralloc.h
@@ -33,7 +33,7 @@
 // V4L2Gralloc is a wrapper around relevant parts of a gralloc module,
 // with some assistive transformations.
 class V4L2Gralloc {
-public:
+ public:
   // Use this method to create V4L2Gralloc objects. Functionally equivalent
   // to "new V4L2Gralloc", except that it may return nullptr in case of failure.
   static V4L2Gralloc* NewV4L2Gralloc();
@@ -49,7 +49,7 @@
   // Release all held locks.
   int unlockAllBuffers();
 
-private:
+ private:
   // Constructor is private to allow failing on bad input.
   // Use NewV4L2Gralloc instead.
   V4L2Gralloc(const gralloc_module_t* module);