nfs: do not export discarded symbols

The function nfs4_pnfs_v3_ds_connect_unload is exported so it can be
used by other modules, but is also marked '__exit' and will be
discarded when built into the kernel, as pointed out by this
linker error:

`nfs4_pnfs_v3_ds_connect_unload' referenced in section `___ksymtab_gpl+nfs4_pnfs_v3_ds_connect_unload' of fs/built-in.o: defined in discarded section `.exit.text' of fs/built-in.o

This removes the __exit annotation to make it safe to call this function.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 5f01d95 ("nfs41: create NFSv3 DS connection if specified")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/pnfs_nfs.c

@@ -561,7 +561,7 @@ static bool load_v3_ds_connect(void)
 	return(get_v3_ds_connect != NULL);
 }
 
-void __exit nfs4_pnfs_v3_ds_connect_unload(void)
+void nfs4_pnfs_v3_ds_connect_unload(void)
 {
 	if (get_v3_ds_connect) {
 		symbol_put(nfs3_set_ds_client);