Documentation/admin-guide: dm-integrity: drop doubled words

Drop the doubled words "on" and "the".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: dm-devel@redhat.com
Link: https://lore.kernel.org/r/20200704032020.21923-4-rdunlap@infradead.org


Signed-off-by: Jonathan Corbet <corbet@lwn.net>