[libata] pata_{legacy,sc1200,sl82c105}: add missing hooks

Alan Cox noticed several hooks in pata_* drivers were missing, when
he authored his ->cable_detect hook patches.  This patch extracts
just those fixes from Alan's patches, adding the necessary hooks
(usually ->freeze, ->thaw, and ->post_internal_cmd) to the drivers.

Signed-off-by: Jeff Garzik <jeff@garzik.org>