[PATCH] libata: fix autopsy ehc->i.action and ehc->i.dev handling

Commit 0662c58b updated
ata_eh_autopsy() to OR determined action to ehc->i.action to preserve
action mask set directly into ehc->i.action by nested functions.  This
broke action mask clearing on SENSE_VALID case causing revalidation
and EH complete message on successful ATAPI CC.

This patch removes two local variables - action and failed_dev - which
cache ehc->i.action and ehc->i.dev respectively, and make the function
directly modify ehc->i.* fields to remove aliasing issues.

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