pktcdvd: fix regression on 64-bit architectures

The support for the compat ioctl did not actually do what it was
supposed to do because of a typo, instead it broke native support for
CDROM_LAST_WRITTEN and CDROM_SEND_PACKET on all architectures with
CONFIG_COMPAT enabled.

Fixes: 1b114b08 ("pktcdvd: add compat_ioctl handler")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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Please apply for v5.5, I just noticed the regression while
rebasing some of the patches I created on top.
Signed-off-by: Jens Axboe <axboe@kernel.dk>