hikey: gralloc Update for new ION interface

4.12+ kernels have an updated ION interface; this adapts hikey's gralloc
to work seemlessly with both old and new kernels' interfaces.

Test: validated with both new and old kernels on hikey, with aosp master

Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
  [sumits: maintain compatibility with older kernels]

Change-Id: Ic30470004b48f14765fdee8179de6d17f7b448b5
diff --git a/gralloc/gralloc_priv.h b/gralloc/gralloc_priv.h
index 3615960..582c487 100644
--- a/gralloc/gralloc_priv.h
+++ b/gralloc/gralloc_priv.h
@@ -110,6 +110,8 @@
 	pthread_mutex_t lock;
 	buffer_handle_t currentBuffer;
 	int ion_client;
+	int system_heap_id;
+	bool gralloc_legacy_ion;
 
 	struct fb_var_screeninfo info;
 	struct fb_fix_screeninfo finfo;