drm/ttm: Fix ttm_backup kerneldoc

The docs were not properly updated from an earlier version of the code.

Fixes: e7b5d23e5d47 ("drm/ttm: Provide a shmem backup implementation")
Cc: Christian König <[e-mail]>
Cc: Matthew Brost <[e-mail]>
Cc: Matthew Auld <[e-mail]>
Cc: [e-mail]
Signed-off-by: Thomas Hellström <[e-mail]>
Reviewed-by: Matthew Brost <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/gpu/drm/ttm/ttm_backup.c

···
  * @backup: The struct backup pointer used to back up the page.
  * @dst: The struct page to copy into.
  * @handle: The handle returned when the page was backed up.
- * @intr: Try to perform waits interruptable or at least killable.
+ * @intr: Try to perform waits interruptible or at least killable.
  *
  * Return: 0 on success, Negative error code on failure, notably
  * -EINTR if @intr was set to true and a signal is pending.

include/drm/ttm/ttm_backup.h

···
  * @handle: The handle to convert.
  *
  * Converts an opaque handle received from the
- * struct ttm_backoup_ops::backup_page() function to an (invalid)
+ * ttm_backup_backup_page() function to an (invalid)
  * struct page pointer suitable for a struct page array.
  *
  * Return: An (invalid) struct page pointer.
···
  *
  * Return: The handle that was previously used in
  * ttm_backup_handle_to_page_ptr() to obtain a struct page pointer, suitable
- * for use as argument in the struct ttm_backup_ops drop() or
- * copy_backed_up_page() functions.
+ * for use as argument in the struct ttm_backup_drop() or
+ * ttm_backup_copy_page() functions.
  */
 static inline unsigned long
 ttm_backup_page_ptr_to_handle(const struct page *page)