raw-posix: cleanup ioctl methods

Rename raw_ioctl and raw_aio_ioctl to hdev_ioctl and hdev_aio_ioctl as they
are only used for the host device.  Also only add them to the method table
for the cases where we need them (generic hdev if linux and linux CDROM)
instead of declaring stubs and always add them.

Signed-off-by: Christoph Hellwig <hch@lst.de>