jmicron ATA: reimplement jmicron ATA quirk

Reimplement jmicron ATA quirk.

* renamed to quirk_jmicron_ata()
* quirk is invoked only for the affected controllers
* programming is stricter.  e.g. conf5 bit24 is cleared if
  unnecessary.
* code factored for readability
* JMB360 and JMB368 are programmed into proper mode

Verified on JMB360, 363 and 368.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>