NFS: remove IS_SWAPFILE hack

This code is pointless as IS_SWAPFILE is always defined.
So remove it.
Suggested-by: Mark Hemment <markhemm@googlemail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/file.c

@@ -44,11 +44,6 @@
 
 static const struct vm_operations_struct nfs_file_vm_ops;
 
-/* Hack for future NFS swap support */
-#ifndef IS_SWAPFILE
-# define IS_SWAPFILE(inode)	(0)
-#endif
-
 int nfs_check_flags(int flags)
 {
 	if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))