[PATCH] libata: ACPI _SDD support

_SDD (Set Device Data) is an ACPI method that is used to tell the
firmware what the identify data is of the device that is attached to
the port.  It is an optional method, and it's ok for it to be missing.
Because of this, we always return success from the routine that calls
this method, even if the execution fails.

Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
(cherry picked from 39aa79e0a1f5f2e28aa341f035940746a98b45b1 commit)