xen: Fix spelling mistake

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

Signed-off-by: Zhang Jiaming <jiaming@nfschina.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220630075027.68833-1-jiaming@nfschina.com


Signed-off-by: Juergen Gross <jgross@suse.com>