gralloc: fix struct private_module_t definition for C usage

Change-Id: I615294c1b2fcf2fd2a7dc465a4b8351f00c8003c
Signed-off-by: Greg Hackmann <ghackmann@google.com>
diff --git a/include/gralloc_priv.h b/include/gralloc_priv.h
index 7cec618..e831c0d 100644
--- a/include/gralloc_priv.h
+++ b/include/gralloc_priv.h
@@ -37,7 +37,7 @@
 struct private_module_t {
     gralloc_module_t base;
 
-    private_handle_t* framebuffer;
+    struct private_handle_t* framebuffer;
     uint32_t flags;
     uint32_t numBuffers;
     uint32_t bufferMask;