gpu: ion: Add callbacks to enable SMI voting in ION.

This change is part of the move from PMEM to ION. ION needs an SMI
voting interface smiliar to PMEM's.

Change-Id: I18888f46198848694fb7e1e0d2671074bf51d7c9
Signed-off-by: Alex Bird <alexbird@codeaurora.org>
diff --git a/drivers/gpu/ion/ion_priv.h b/drivers/gpu/ion/ion_priv.h
index 888b599..ac51854 100644
--- a/drivers/gpu/ion/ion_priv.h
+++ b/drivers/gpu/ion/ion_priv.h
@@ -86,6 +86,7 @@
  * @map_kernel		map memory to the kernel
  * @unmap_kernel	unmap memory to the kernel
  * @map_user		map memory to userspace
+ * @unmap_user		unmap memory to userspace
  */
 struct ion_heap_ops {
 	int (*allocate) (struct ion_heap *heap,
@@ -102,6 +103,7 @@
 	void (*unmap_kernel) (struct ion_heap *heap, struct ion_buffer *buffer);
 	int (*map_user) (struct ion_heap *mapper, struct ion_buffer *buffer,
 			 struct vm_area_struct *vma, unsigned long flags);
+	void (*unmap_user) (struct ion_heap *mapper, struct ion_buffer *buffer);
 	int (*cache_op)(struct ion_heap *heap, struct ion_buffer *buffer,
 			void *vaddr, unsigned int offset,
 			unsigned int length, unsigned int cmd);