Linux 4.9: inode_change_ok() becomes setattr_prepare()

Linux 4.9: inode_change_ok() becomes setattr_prepare()

Linux commit 31051c85b5e2 "fs: Give dentry to inode_change_ok() instead
of inode" renames and modifies inode_change_ok(inode, attrs) to
setattr_prepare(dentry, attrs).

Modify OpenAFS to cope.

Change-Id: I72f8dfbdbd25d7c775e9c35116e323ea4359e95c
Reviewed-on: https://gerrit.openafs.org/12418
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>