libata: convert the remaining PATA drivers to new init model

Convert pdc_adma, pata_cs5520, pata_isapnp, pata_ixp4xx_cf,
pata_legacy, pata_mpc52xx, pata_mpiix, pata_pcmcia, pata_pdc2027x,
pata_platform, pata_qdi, pata_scc and pata_winbond to new init model.

* init_one()'s now follow more consistent init order

* cs5520 now registers one host with two ports, not two hosts.  If any
  of the two ports are disabled, it's made dummy as other drivers do.

Tested pdc_adma and pata_legacy.  Both are as broken as before.  The
rest are compile tested only.

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