ion: add new ion_user_handle_t type for the user-space token

Declare new ion_user_handle_t type to contain the token returned to user-space.
This allows a 2-step migration of the user-space code to a new kernel header
first, then will allow us to change the definition of the ion_user_handle_type_t
to int without breaking the API.
Signed-off-by: Rom Lemarchand <romlem@google.com>
(cherry picked from commit ebb8269bbb05b06ecedca3e21b3e65f23d48eadd)
[jstultz: modified patch to apply to staging directory]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/ion/ion.c

@@ -1139,7 +1139,7 @@ static long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (IS_ERR(handle))
 			return PTR_ERR(handle);
 
-		data.handle = (struct ion_handle *)handle->id;
+		data.handle = (ion_user_handle_t)handle->id;
 
 		if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
 			ion_free(client, handle);
@@ -1191,7 +1191,7 @@ static long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (IS_ERR(handle))
 			ret = PTR_ERR(handle);
 		else
-			data.handle = (struct ion_handle *)handle->id;
+			data.handle = (ion_user_handle_t)handle->id;
 
 		if (copy_to_user((void __user *)arg, &data,
 				 sizeof(struct ion_fd_data)))

drivers/staging/android/ion/ion.h

@@ -20,6 +20,8 @@
 #include <linux/types.h>
 
 struct ion_handle;
+typedef struct ion_handle *ion_user_handle_t;
+
 /**
  * enum ion_heap_types - list of all possible types of heaps
  * @ION_HEAP_TYPE_SYSTEM:	 memory allocated via vmalloc
@@ -268,7 +270,7 @@ struct ion_allocation_data {
 	size_t align;
 	unsigned int heap_id_mask;
 	unsigned int flags;
-	struct ion_handle *handle;
+	ion_user_handle_t handle;
 };
 
 /**
@@ -282,7 +284,7 @@ struct ion_allocation_data {
  * provides the file descriptor and the kernel returns the handle.
  */
 struct ion_fd_data {
-	struct ion_handle *handle;
+	ion_user_handle_t handle;
 	int fd;
 };
 
@@ -291,7 +293,7 @@ struct ion_fd_data {
  * @handle:	a handle
  */
 struct ion_handle_data {
-	struct ion_handle *handle;
+	ion_user_handle_t handle;
 };
 
 /**