Fuzzing the Linux kernel with syzkaller allowed to find how to crash qemu
using a special SCSI_IOCTL_SEND_COMMAND. It hits the assertion in
ide_dma_cb() introduced in the commit a718978e in July 2015.
Currently this bug is not reproduced by the unit tests.

Let's improve the ide-test to cover more PRDT cases including one
that causes this particular qemu crash.

The test is developed according to the Programming Interface for
Bus Master IDE Controller (Revision 1.0 5/16/94).
Signed-off-by: NAlexander Popov <alex.popov@linux.com>
Message-id: 20191223175117.508990-3-alex.popov@linux.com
Signed-off-by: NJohn Snow <jsnow@redhat.com>