[PATCH] libata: clean up debounce parameters and improve parameter selection

The names of predefined debounce timing parameters didn't exactly
match their usages.  Rename to more generic names and implement param
selection helper sata_ehc_deb_timing() which uses EHI_HOTPLUGGED to
select params.

Combined with the previous EHI_RESUME_LINK differentiation, this makes
parameter selection accurate.  e.g. user scan resumes link but normal
deb param is used instead of hotplug param.

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