* Fix icside, cris-ide, au1xxx-ide, amd74xx, via82cxxx and pmac host drivers
  to use ide_rate_filter().

  This results in the following modes (from user requests) being clipped down:
  - invalid modes (values 0x46-0xFF)  [ for all hosts ]
  - unsupported by a host UDMA modes  [ for hosts which support UDMA]
  - all UDMA modes and MWDMA3-4 modes [ for hosts which don't support UDMA ]
  - invalid modes (values 0x25-0x39)  [ for hosts which don't support UDMA ]

* Host driver specific changes in behavior:

  icside:
    - no change

  cris-ide
    - clip unsupported UDMA3-6 modes down
    - fix BUG() on trying to set unsupported UDMA3-6 modes

  au1xxx-ide/pmac
    - clip unsupported UDMA modes down

  amd74xx/via82cxxx
    - clip unsupported UDMA modes down
    - fix random PIO timings being set for unsupported/invalid modes
    - fix unsupported/invalid modes being set on the device

* While at it remove no longer needed checks from pmac.c driver.

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