NFS: Ignore NFS_INO_REVAL_FORCED in nfs_check_inode_attributes()

If we hold a delegation, we should not need to call
nfs_check_inode_attributes() since we already know which attributes
are valid, and which ones may still need revalidation. The state
of the NFS_INO_REVAL_FORCED flag is therefore irrelevant.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>