cifs: Fix typo 'CIFS_NFSD_EXPORT'

It should be 'CONFIG_CIFS_NFSD_EXPORT'. No-one noticed because that
symbol depends on BROKEN.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Steve French <smfrench@gmail.com>

fs/cifs/cifsfs.h

@@ -121,9 +121,9 @@ extern ssize_t	cifs_getxattr(struct dentry *, const char *, void *, size_t);
 extern ssize_t	cifs_listxattr(struct dentry *, char *, size_t);
 extern long cifs_ioctl(struct file *filep, unsigned int cmd, unsigned long arg);
 
-#ifdef CIFS_NFSD_EXPORT
+#ifdef CONFIG_CIFS_NFSD_EXPORT
 extern const struct export_operations cifs_export_ops;
-#endif /* CIFS_NFSD_EXPORT */
+#endif /* CONFIG_CIFS_NFSD_EXPORT */
 
 #define CIFS_VERSION   "1.75"
 #endif				/* _CIFSFS_H */