libata: fix revalidation issuing after configuration commands

After commands which can change device configuration, EH is scheduled
to revalidate and reconfigure the device.  Host link was incorrectly
used unconditionally when scheduling EH action.  This resulted in
bogus revalidation request and mismatched configuration between device
and driver.  Fix it.

This bug was reported by Igor Durdanovic.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Igor Durdanovic <idurdanovic@comcast.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>