libata: fallback to the other IDENTIFY on device error, take#2

It seems the world isn't as frank as we thought and some devices lie
about who they are.  Fallback to the other IDENTIFY if IDENTIFY is
aborted by the device.  As this is the strategy used by IDE for a long
time, it shouldn't cause too much problem.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: William Thompson <wt@electro-mechanical.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>