remove broken direct I/O size ioctl

This ioctl tries to second guess direct I/O parameters which aren't a filesystem drivers business and shouldn't be exposed as an ioctl to start with.

Index: linux-2.6/fs/xfs/linux-2.6/xfs_ioctl32.c
===================================================================
@@ -115,7 +115,6 @@
 	vnode_t		*vp = LINVFS_GET_VP(inode);
 
 	switch (cmd) {
-	case XFS_IOC_DIOINFO:
 	case XFS_IOC_FSGEOMETRY_V1:
 	case XFS_IOC_FSGEOMETRY:
 	case XFS_IOC_GETVERSION:

Unfortunately there are some applications that will now start to see errors from this ioctl if we go this route - whereas before they would've been "functional", now they will break. So, I think we need a different solution here. Yes, I agree its a stupid call to have on Linux, but here we are, and apps ported straight from IRIX have been made to use this.

cheers.

Nathan