NFS: Remove an incorrect revalidation in nfs4_update_changeattr_locked()

In nfs4_update_changeattr_locked(), we don't need to set the
NFS_INO_REVAL_PAGECACHE flag, because we already know the value of the
change attribute, and we're already flagging the size. In fact, this
forces us to revalidate the change attribute a second time for no good
reason.
This extra flag appears to have been introduced as part of the xattr
feature, when update_changeattr_locked() was converted for use by the
xattr code.

Fixes: 1b523ca9

 ("nfs: modify update_changeattr to deal with regular files")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>