o not only getting 0xff handling right for
SATA is, well, the right thing to do, it's much more important now.

This patch makes the following changes.

* Make ata_bus_softreset() return -ENODEV if any of its wait fails
  due to 0xff status.

* Fail soft/hardreset if status wait returns -ENODEV indicating 0xff
  status while SStatus says the link is online.  e.g. Reset fails if
  status is 0xff after reset when SStatus reports the linke is online.
  If SCR registers are not available, everything is the same as
  before.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
JE