macio: fix overflow in lba to offset conversion for ATAPI devices

As the IDEState lba field is an int32_t, make sure we cast to int64_t before
shifting to calculate the offset. Otherwise we end up with an overflow when
trying to access sectors beyond 2GB as can occur when using DVD images.

[Maintainer edit: fixed extraneous parentheses. --js]

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 1451928613-29476-1-git-send-email-mark.cave-ayland@ilande.co.uk
Signed-off-by: John Snow <jsnow@redhat.com>
