drm: drm_bufs.c: Adjust end of block comment

Add a new line with */ on the last line of a block comment to follow the
Linux kernel coding conventions.
Problem found by checkpatch.

Signed-off-by: Beatriz Martins de Carvalho <martinsdecarvalhobeatriz@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/c3a261994b88f6fc39f69ee8c1af8ab115d76a87.1618756333.git.martinsdecarvalhobeatriz@gmail.com

drivers/gpu/drm/drm_bufs.c

@@ -325,7 +325,8 @@ static int drm_addmap_core(struct drm_device *dev, resource_size_t offset,
 		/* dma_addr_t is 64bit on i386 with CONFIG_HIGHMEM64G,
 		 * As we're limiting the address to 2^32-1 (or less),
 		 * casting it down to 32 bits is no problem, but we
-		 * need to point to a 64bit variable first. */
+		 * need to point to a 64bit variable first.
+		 */
 		map->handle = dma_alloc_coherent(dev->dev,
 						 map->size,
 						 &map->offset,