sata_fsl: Defer non-ncq commands when ncq commands active

Fix for non-ncq & ncq commands causing timeouts when both are issued
simultaneously to the same device.

Signed-off-by: Ashish Kalra <Ashish.Kalra@freescale.com>
[fixed to be actual compileable C code -jg]
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>