[PATCH] libata-dev: fix the device err check sequence (respin)

Current irq-pio checks ERR bit and stops on ERR before it does anything else.
This behavior doesn't look right.
The DRQ bit should take higher precedence than the ERR bit.

Changes:
- Let the HSM do the data transfer whenever the
  device asks for DRQ bit, even if the ERR bit is set.
- For DRQ=1 ERR=1, don't trust the data

Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>