gpu: ion: Add IS_CACHED macro

Add a proper IS_CACHED macro for detecting whether or not
flags indicated a cached mapping.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
diff --git a/include/linux/ion.h b/include/linux/ion.h
index 91cbbda..15ba708 100644
--- a/include/linux/ion.h
+++ b/include/linux/ion.h
@@ -69,6 +69,8 @@
 
 #define ION_SET_CACHE(__cache)  ((__cache) << ION_CACHE_SHIFT)
 
+#define ION_IS_CACHED(__flags)	((__flags) & (1 << ION_CACHE_SHIFT))
+
 #ifdef __KERNEL__
 struct ion_device;
 struct ion_heap;