nilfs2: cpfile: fix some kernel-doc warnings

Correct the function parameter names for nilfs_cpfile_get_info():

cpfile.c:564: warning: Function parameter or member 'cnop' not described in 'nilfs_cpfile_get_cpinfo'
cpfile.c:564: warning: Function parameter or member 'mode' not described in 'nilfs_cpfile_get_cpinfo'
cpfile.c:564: warning: Function parameter or member 'buf' not described in 'nilfs_cpfile_get_cpinfo'
cpfile.c:564: warning: Function parameter or member 'cisz' not described in 'nilfs_cpfile_get_cpinfo'
cpfile.c:564: warning: Excess function parameter 'cno' description in 'nilfs_cpfile_get_cpinfo'
cpfile.c:564: warning: Excess function parameter 'ci' description in 'nilfs_cpfile_get_cpinfo'

Also add missing descriptions of the function's specification.

[ konishi.ryusuke@gmail.com: filled in missing descriptions ]

Link: https://lkml.kernel.org/r/20231220065931.2372-1-rdunlap@infradead.org
Link: https://lkml.kernel.org/r/20231220221342.11505-1-konishi.ryusuke@gmail.com


Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>