This patch reimplement ata_hpa_resize() such that...

* All HPA related decisions are made inside ata_hpa_resize() proper.
  ata_hpa_resize() returns 0 if configuration can proceed, -errno if
  device needs to be reset and reconfigured.

* All errors are handled properly.  If HPA unlocking isn't requested,
  HPA handling is disabled automatically to avoid unnecessary device
  detection failure.

* Messages are trimmed.  HPA detection message is printed only during
  initial configuration.  HPA unlocked message is printed only during
  initial configuration or unlocking results in different size.

* Instead of using sectors returned in TF of SET_MAX, re-read IDENTIFY
  data as that's the value the device is going to use.

* It's called early during ata_dev_configure() as IDENTIFY data might
  change after resizing.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>