fuse: fuse_i.h: clean up kernel-doc comments

fuse: fuse_i.h: clean up kernel-doc comments

Convert many comments to kernel-doc format to eliminate around 20
kernel-doc warnings like these:

Warning: fs/fuse/fuse_i.h:374 This comment starts with '/**', but isn't a kernel-doc comment. Refer to Documentation/doc-guide/kernel-doc.rst
 * A Fuse connection.
Warning: fs/fuse/fuse_i.h:817 This comment starts with '/**', but isn't a kernel-doc comment. Refer to Documentation/doc-guide/kernel-doc.rst
 * Get a filled in inode
Warning: fs/fuse/fuse_i.h:859 This comment starts with '/**', but isn't a kernel-doc comment. Refer to Documentation/doc-guide/kernel-doc.rst
 * Send RELEASE or RELEASEDIR request
and more like this.

Also add struct member and function parameter descriptions to avoid
these warnings:

Warning: fs/fuse/fuse_i.h:1071 struct member 'epoch_work' not described in 'fuse_conn'
Warning: fs/fuse/fuse_i.h:1071 struct member 'rcu' not described in 'fuse_conn'
Warning: fs/fuse/fuse_i.h:1423 function parameter 'fc' not described in 'fuse_reverse_inval_inode'
Warning: fs/fuse/fuse_i.h:1423 function parameter 'nodeid' not described in 'fuse_reverse_inval_inode'
Warning: fs/fuse/fuse_i.h:1423 function parameter 'offset' not described in 'fuse_reverse_inval_inode'
Warning: fs/fuse/fuse_i.h:1423 function parameter 'len' not described in 'fuse_reverse_inval_inode'
Warning: fs/fuse/fuse_i.h:1436 function parameter 'fc' not described in 'fuse_reverse_inval_entry'
Warning: fs/fuse/fuse_i.h:1436 function parameter 'parent_nodeid' not described in 'fuse_reverse_inval_entry'
Warning: fs/fuse/fuse_i.h:1436 function parameter 'child_nodeid' not described in 'fuse_reverse_inval_entry'
Warning: fs/fuse/fuse_i.h:1436 function parameter 'name' not described in 'fuse_reverse_inval_entry'
Warning: fs/fuse/fuse_i.h:1436 function parameter 'flags' not described in 'fuse_reverse_inval_entry'

Convert struct fuse_file, struct fuse_submount_lookup, struct fuse_inode,
and struct fuse_conn to kernel-doc.

Convert these to plain comments:
Warning: fs/fuse/fuse_i.h:1423 expecting prototype for File(). Prototype was for fuse_reverse_inval_inode() instead
Warning: fs/fuse/fuse_i.h:1436 expecting prototype for File(). Prototype was for fuse_reverse_inval_entry() instead

Change some "/**" to "/*" since they are not kernel-doc comments.

The changes above fix most kernel-doc warnings in this file but
these warnings are not fixed and still remain:
Warning: fs/fuse/fuse_i.h:1428 No description found for return value of 'fuse_fill_super_common'
Warning: fs/fuse/fuse_i.h:1455 No description found for return value of 'fuse_ctl_add_conn'

Binary build output is the same before and after these changes.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>