fs: fix fs/namei.c kernel-doc warnings

Fix kernel-doc warnings in fs/namei.c:

Warning(fs/namei.c:360): No description found for parameter 'inode'
Warning(fs/namei.c:672): No description found for parameter 'nd'

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Cc:	Alexander Viro <viro@zeniv.linux.org.uk>
Cc:	linux-fsdevel@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>