ide: add struct ide_port_ops (take 2)

* Move hooks for port/host specific methods from ide_hwif_t to
  'struct ide_port_ops'.

* Add 'const struct ide_port_ops *port_ops' to 'struct ide_port_info'
  and ide_hwif_t.

* Update host drivers and core code accordingly.

While at it:

* Rename ata66_*() cable detect functions to *_cable_detect() to match
  the standard naming. (Suggested by Sergei Shtylyov)

v2:
* Fix build for bast-ide. (Noticed by Andrew Morton)

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>