nfs: remove nfs_wait_atomic_killable() and nfs_write_prepare() declaration

nfs_write_prepare() has been removed since
commit a4cdda59 ("NFS: Create a common pgio_rpc_prepare
function"), so remove it.

nfs_wait_atomic_killable() has been removed since
commit 723c921e ("sched/wait, fs/nfs: Convert wait_on_atomic_t()
usage to the new wait_var_event() API"), so remove it.
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/internal.h

@@ -435,7 +435,6 @@ extern void nfs_zap_acl_cache(struct inode *inode);
 extern void nfs_set_cache_invalid(struct inode *inode, unsigned long flags);
 extern bool nfs_check_cache_invalid(struct inode *, unsigned long);
 extern int nfs_wait_bit_killable(struct wait_bit_key *key, int mode);
-extern int nfs_wait_atomic_killable(atomic_t *p, unsigned int mode);
 
 /* super.c */
 extern const struct super_operations nfs_sops;
@@ -503,7 +502,6 @@ extern void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
 			const struct nfs_pgio_completion_ops *compl_ops);
 extern void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio);
 extern void nfs_commit_free(struct nfs_commit_data *p);
-extern void nfs_write_prepare(struct rpc_task *task, void *calldata);
 extern void nfs_commit_prepare(struct rpc_task *task, void *calldata);
 extern int nfs_initiate_commit(struct rpc_clnt *clnt,
 			       struct nfs_commit_data *data,