Use IDMA for ATAPI commands.  Write and some misc commands time out
when executed using ATAPI_PROT_DMA but ATAPI_PROT_PIO works fine.  As
PIO is driven by DMA too, it doesn't make any noticeable difference
for native SATA devices.  inic_check_atapi_dma() is implemented to
force PIO for those ATAPI commands.

After this change, sata_inic162x issues all commands using IDMA.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>