dma-buf: add support for compat ioctl

Add compat ioctl support to dma-buf. This lets one to use DMA_BUF_IOCTL_SYNC
ioctl from 32bit application on 64bit kernel. Data structures for both 32
and 64bit modes are same, so there is no need for additional translation
layer.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1487683261-2655-1-git-send-email-m.szyprowski@samsung.com

drivers/dma-buf/dma-buf.c

@@ -325,6 +325,9 @@ static const struct file_operations dma_buf_fops = {
 	.llseek		= dma_buf_llseek,
 	.poll		= dma_buf_poll,
 	.unlocked_ioctl	= dma_buf_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= dma_buf_ioctl,
+#endif
 };
 
 /*