ata: update ata port's runtime status during system resume

The ata port is brought back to full power state during system resume.
So its runtime PM status will have to be updated to reflect
the actual post-system sleep status.

This also fixes below warning during system suspend/resume.

WARNING: at /work/linux/drivers/ata/libata-eh.c:4034
ata_scsi_port_error_handler+0x89/0x557()

4034         WARN_ON(!(ap->pflags & ATA_PFLAG_SUSPENDED));

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>