commit 6b66d958 didn't handle SATA PMP
case in ata_acpi_bind_device and will cause a NULL ptr dereference when
user attached a SATA drive to the PMP port. Fix this by checking PMP
support.

This bug is reported by Dan van der Ster in the following bugzilla page:
https://bugzilla.kernel.org/show_bug.cgi?id=48211Reported-by: Dan van der Ster <dan@vanderster.com>
Tested-by: Dan van der Ster <dan@vanderster.com>
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Tested-by: Simon <tangouniform@sbcglobal.net>