dma-buf/sw_sync: de-stage SW_SYNC

SW_SYNC allows to run tests on the sync_file framework via debugfs on

<debugfs>/sync/sw_sync

Opening and closing the file triggers creation and release of a sync
timeline. To create fences on this timeline the SW_SYNC_IOC_CREATE_FENCE
ioctl should be used. To increment the timeline value use SW_SYNC_IOC_INC.

Also it exports Sync information on

<debugfs>/sync/info

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
index f353db2..210a10b 100644
--- a/drivers/dma-buf/Makefile
+++ b/drivers/dma-buf/Makefile
@@ -1,2 +1,3 @@
 obj-y := dma-buf.o fence.o reservation.o seqno-fence.o fence-array.o
 obj-$(CONFIG_SYNC_FILE)		+= sync_file.o
+obj-$(CONFIG_SW_SYNC)		+= sw_sync.o sync_debug.o