virtio-balloon: fix a typo in comment of virtballoon_migratepage()

Typo: compation --> compaction

Signed-off-by: Liu Xiang <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Michael S. Tsirkin <[e-mail]>
Reviewed-by: David Hildenbrand <[e-mail]>

drivers/virtio/virtio_balloon.c

···
 #ifdef CONFIG_BALLOON_COMPACTION
 /*
  * virtballoon_migratepage - perform the balloon page migration on behalf of
- *			     a compation thread.     (called under page lock)
+ *			     a compaction thread.     (called under page lock)
  * @vb_dev_info: the balloon device
  * @newpage: page that will replace the isolated page after migration finishes.
  * @page   : the isolated (old) page that is about to be migrated to newpage.