libata/ahci: Fix PCS quirk application

Commit c312ef17

 "libata/ahci: Drop PCS quirk for Denverton and
beyond" got the polarity wrong on the check for which board-ids should
have the quirk applied. The board type board_ahci_pcs7 is defined at the
end of the list such that "pcs7" boards can be special cased in the
future if they need the quirk. All prior Intel board ids "<
board_ahci_pcs7" should proceed with applying the quirk.

Reported-by: Andreas Friedrich <afrie@gmx.net>
Reported-by: Stephen Douthit <stephend@silicom-usa.com>
Fixes: c312ef17

 ("libata/ahci: Drop PCS quirk for Denverton and beyond")
Cc: <stable@vger.kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>