sata_mv: add the Gen IIE flag to the SoC devices.

The SoC sata port is based on the 7042/6042 devices (Gen IIE). This patch
will fix various issues when working with PMP and/or NCQ.

Signed-off-by: Saeed Bishara <saeed@marvell.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>