drm/i915/dmabuf: Update dma_buf_ops.unmap_dma_buf callback to use drm_gem_unmap_dma_buf()

The dma_buf_ops.unmap_dma_buf callback used in i915,
i915_gem_unmap_dma_buf(), has the same code as drm_gem_unmap_dma_buf().
In order to eliminate defining and using duplicate function, it updates
the dma_buf_ops.unmap_dma_buf callback to use drm_gem_unmap_dma_buf().
Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220225131316.1433515-2-gwan-gyeong.mun@intel.com

drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c

@@ -66,15 +66,6 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme
 	return ERR_PTR(ret);
 }
 
-static void i915_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
-				   struct sg_table *sg,
-				   enum dma_data_direction dir)
-{
-	dma_unmap_sgtable(attachment->dev, sg, dir, DMA_ATTR_SKIP_CPU_SYNC);
-	sg_free_table(sg);
-	kfree(sg);
-}
-
 static int i915_gem_dmabuf_vmap(struct dma_buf *dma_buf,
 				struct iosys_map *map)
 {
@@ -209,7 +200,7 @@ static const struct dma_buf_ops i915_dmabuf_ops =  {
 	.attach = i915_gem_dmabuf_attach,
 	.detach = i915_gem_dmabuf_detach,
 	.map_dma_buf = i915_gem_map_dma_buf,
-	.unmap_dma_buf = i915_gem_unmap_dma_buf,
+	.unmap_dma_buf = drm_gem_unmap_dma_buf,
 	.release = drm_gem_dmabuf_release,
 	.mmap = i915_gem_dmabuf_mmap,
 	.vmap = i915_gem_dmabuf_vmap,