gpu: ion: fix compilation warning

use atomic_read to get the refcount value to avoid compilation warning

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
[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

@@ -1233,7 +1233,8 @@ static int ion_debug_heap_show(struct seq_file *s, void *unused)
 		total_size += buffer->size;
 		if (!buffer->handle_count) {
 			seq_printf(s, "%16.s %16u %16u %d %d\n", buffer->task_comm,
-				   buffer->pid, buffer->size, buffer->kmap_cnt, buffer->ref);
+				   buffer->pid, buffer->size, buffer->kmap_cnt,
+				   atomic_read(&buffer->ref.refcount));
 			total_orphaned_size += buffer->size;
 		}
 	}