dm_comressor_info -> dm_compressor_info

The kernel-doc markup is right, but the struct itself
and their references contain a typo.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/9de495fa791596609eb2e73ba71cea99e09b2689.1603791716.git.mchehab+huawei@kernel.orgSigned-off-by: Jonathan Corbet <corbet@lwn.net>