[XFS] fix compile on 32 bit systems

The recent compat patches make xfs_file.c include xfs_ioctl32.h unconditional,
which breaks the build on 32 bit systems which don't have the various compat
defintions.

Remove the include and move the defintion of xfs_file_compat_ioctl to
xfs_ioctl.h so that we can avoid including all the compat defintions in
xfs_file.c

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>