xen: Fix spelling mistake

Change 'maped' to 'mapped'.
Change 'unmaped' to 'unmapped'.

Signed-off-by: Zhang Jiaming <[e-mail]>
Reviewed-by: Juergen Gross <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Juergen Gross <[e-mail]>

drivers/xen/xen-front-pgdir-shbuf.c

···
  * shared by the frontend itself) or map the provided granted
  * references onto the backing storage (buf->pages).
  *
- * \param buf shared buffer which grants to be maped.
+ * \param buf shared buffer which grants to be mapped.
  * \return zero on success or a negative number on failure.
  */
 int xen_front_pgdir_shbuf_map(struct xen_front_pgdir_shbuf *buf)
···
  * shared by the frontend itself) or unmap the provided granted
  * references.
  *
- * \param buf shared buffer which grants to be unmaped.
+ * \param buf shared buffer which grants to be unmapped.
  * \return zero on success or a negative number on failure.
  */
 int xen_front_pgdir_shbuf_unmap(struct xen_front_pgdir_shbuf *buf)