gpu: ion: Add support for flushing via fd

Userspace clients pass fds around, not handles. Support flushing
via fd.

Change-Id: Ic22d9327e9fa72cb604c3010a2a6f798be8dfdb1
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
diff --git a/include/linux/ion.h b/include/linux/ion.h
index 7de40d4..89ac992 100644
--- a/include/linux/ion.h
+++ b/include/linux/ion.h
@@ -438,6 +438,7 @@
 /* struct ion_flush_data - data passed to ion for flushing caches
  *
  * @handle:	handle with data to flush
+ * @fd:		fd to flush
  * @vaddr:	userspace virtual address mapped with mmap
  * @offset:	offset into the handle to flush
  * @length:	length of handle to flush
@@ -448,6 +449,7 @@
  */
 struct ion_flush_data {
 	struct ion_handle *handle;
+	int fd;
 	void *vaddr;
 	unsigned int offset;
 	unsigned int length;