[PATCH] libata: fix ATA_EH_REVALIDATE clearing

ATA_EH_REVALIDATE should be cleared after all devices on the target
port have been revalidated.  Fix ata_eh_revalidate_and_attach()
accordingly.

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