block/raw-posix: avoid bogus fixup for cylinders on DASD disks

block/raw-posix: avoid bogus fixup for cylinders on DASD disks

large volume DASD that have > 64k cylinders do claim to have
0xFFFE cylinders as special value in the old 16 bit field. We
want to pass this "token" along to the guest, instead of
calculating the real number. Otherwise qemu might fail with
"cyls must be between 1 and 65535"

Cc: qemu-stable@nongnu.org
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 972b543c6b63579aee590b738d21af09f01569f7)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>