fs: fix kernel-doc markups

Two markups are at the wrong place. Kernel-doc only
support having the comment just before the identifier.

Also, some identifiers have different names between their
prototypes and the kernel-doc markup.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/96b1e1b388600ab092331f6c4e88ff8e8779ce6c.1610610937.git.mchehab+huawei@kernel.org


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