drm/amdgpu: add FENCE_TO_HANDLE ioctl that returns syncobj or sync_file

for being able to convert an amdgpu fence into one of the handles.
Mesa will use this.

Reviewed-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Marek Olšák <marek.olsak@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 9816f50..ad02d3f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -70,9 +70,10 @@
  * - 3.18.0 - Export gpu always on cu bitmap
  * - 3.19.0 - Add support for UVD MJPEG decode
  * - 3.20.0 - Add support for local BOs
+ * - 3.21.0 - Add DRM_AMDGPU_FENCE_TO_HANDLE ioctl
  */
 #define KMS_DRIVER_MAJOR	3
-#define KMS_DRIVER_MINOR	20
+#define KMS_DRIVER_MINOR	21
 #define KMS_DRIVER_PATCHLEVEL	0
 
 int amdgpu_vram_limit = 0;